blob: a127cc03c9fa2868739ded1b98c7cd6d0d7ecc8b [file] [log] [blame]
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001/*
Mingming Cao617ba132006-10-11 01:20:53 -07002 * linux/fs/ext4/inode.c
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003 *
4 * Copyright (C) 1992, 1993, 1994, 1995
5 * Remy Card (card@masi.ibp.fr)
6 * Laboratoire MASI - Institut Blaise Pascal
7 * Universite Pierre et Marie Curie (Paris VI)
8 *
9 * from
10 *
11 * linux/fs/minix/inode.c
12 *
13 * Copyright (C) 1991, 1992 Linus Torvalds
14 *
15 * Goal-directed block allocation by Stephen Tweedie
16 * (sct@redhat.com), 1993, 1998
17 * Big-endian to little-endian byte-swapping/bitmaps by
18 * David S. Miller (davem@caip.rutgers.edu), 1995
19 * 64-bit file support on 64-bit platforms by Jakub Jelinek
20 * (jj@sunsite.ms.mff.cuni.cz)
21 *
Mingming Cao617ba132006-10-11 01:20:53 -070022 * Assorted race fixes, rewrite of ext4_get_block() by Al Viro, 2000
Dave Kleikampac27a0e2006-10-11 01:20:50 -070023 */
24
25#include <linux/module.h>
26#include <linux/fs.h>
27#include <linux/time.h>
Mingming Caodab291a2006-10-11 01:21:01 -070028#include <linux/ext4_jbd2.h>
29#include <linux/jbd2.h>
Dave Kleikampac27a0e2006-10-11 01:20:50 -070030#include <linux/smp_lock.h>
31#include <linux/highuid.h>
32#include <linux/pagemap.h>
33#include <linux/quotaops.h>
34#include <linux/string.h>
35#include <linux/buffer_head.h>
36#include <linux/writeback.h>
37#include <linux/mpage.h>
38#include <linux/uio.h>
39#include <linux/bio.h>
40#include "xattr.h"
41#include "acl.h"
42
Dave Kleikampac27a0e2006-10-11 01:20:50 -070043/*
44 * Test whether an inode is a fast symlink.
45 */
Mingming Cao617ba132006-10-11 01:20:53 -070046static int ext4_inode_is_fast_symlink(struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -070047{
Mingming Cao617ba132006-10-11 01:20:53 -070048 int ea_blocks = EXT4_I(inode)->i_file_acl ?
Dave Kleikampac27a0e2006-10-11 01:20:50 -070049 (inode->i_sb->s_blocksize >> 9) : 0;
50
51 return (S_ISLNK(inode->i_mode) && inode->i_blocks - ea_blocks == 0);
52}
53
54/*
Mingming Cao617ba132006-10-11 01:20:53 -070055 * The ext4 forget function must perform a revoke if we are freeing data
Dave Kleikampac27a0e2006-10-11 01:20:50 -070056 * which has been journaled. Metadata (eg. indirect blocks) must be
57 * revoked in all cases.
58 *
59 * "bh" may be NULL: a metadata block may have been freed from memory
60 * but there may still be a record of it in the journal, and that record
61 * still needs to be revoked.
62 */
Mingming Cao617ba132006-10-11 01:20:53 -070063int ext4_forget(handle_t *handle, int is_metadata, struct inode *inode,
64 struct buffer_head *bh, ext4_fsblk_t blocknr)
Dave Kleikampac27a0e2006-10-11 01:20:50 -070065{
66 int err;
67
68 might_sleep();
69
70 BUFFER_TRACE(bh, "enter");
71
72 jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
73 "data mode %lx\n",
74 bh, is_metadata, inode->i_mode,
75 test_opt(inode->i_sb, DATA_FLAGS));
76
77 /* Never use the revoke function if we are doing full data
78 * journaling: there is no need to, and a V1 superblock won't
79 * support it. Otherwise, only skip the revoke on un-journaled
80 * data blocks. */
81
Mingming Cao617ba132006-10-11 01:20:53 -070082 if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
83 (!is_metadata && !ext4_should_journal_data(inode))) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -070084 if (bh) {
Mingming Caodab291a2006-10-11 01:21:01 -070085 BUFFER_TRACE(bh, "call jbd2_journal_forget");
Mingming Cao617ba132006-10-11 01:20:53 -070086 return ext4_journal_forget(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070087 }
88 return 0;
89 }
90
91 /*
92 * data!=journal && (is_metadata || should_journal_data(inode))
93 */
Mingming Cao617ba132006-10-11 01:20:53 -070094 BUFFER_TRACE(bh, "call ext4_journal_revoke");
95 err = ext4_journal_revoke(handle, blocknr, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -070096 if (err)
Mingming Cao617ba132006-10-11 01:20:53 -070097 ext4_abort(inode->i_sb, __FUNCTION__,
Dave Kleikampac27a0e2006-10-11 01:20:50 -070098 "error %d when attempting revoke", err);
99 BUFFER_TRACE(bh, "exit");
100 return err;
101}
102
103/*
104 * Work out how many blocks we need to proceed with the next chunk of a
105 * truncate transaction.
106 */
107static unsigned long blocks_for_truncate(struct inode *inode)
108{
109 unsigned long needed;
110
111 needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
112
113 /* Give ourselves just enough room to cope with inodes in which
114 * i_blocks is corrupt: we've seen disk corruptions in the past
115 * which resulted in random data in an inode which looked enough
Mingming Cao617ba132006-10-11 01:20:53 -0700116 * like a regular file for ext4 to try to delete it. Things
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700117 * will go a bit crazy if that happens, but at least we should
118 * try not to panic the whole kernel. */
119 if (needed < 2)
120 needed = 2;
121
122 /* But we need to bound the transaction so we don't overflow the
123 * journal. */
Mingming Cao617ba132006-10-11 01:20:53 -0700124 if (needed > EXT4_MAX_TRANS_DATA)
125 needed = EXT4_MAX_TRANS_DATA;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700126
Mingming Cao617ba132006-10-11 01:20:53 -0700127 return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700128}
129
130/*
131 * Truncate transactions can be complex and absolutely huge. So we need to
132 * be able to restart the transaction at a conventient checkpoint to make
133 * sure we don't overflow the journal.
134 *
135 * start_transaction gets us a new handle for a truncate transaction,
136 * and extend_transaction tries to extend the existing one a bit. If
137 * extend fails, we need to propagate the failure up and restart the
138 * transaction in the top-level truncate loop. --sct
139 */
140static handle_t *start_transaction(struct inode *inode)
141{
142 handle_t *result;
143
Mingming Cao617ba132006-10-11 01:20:53 -0700144 result = ext4_journal_start(inode, blocks_for_truncate(inode));
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700145 if (!IS_ERR(result))
146 return result;
147
Mingming Cao617ba132006-10-11 01:20:53 -0700148 ext4_std_error(inode->i_sb, PTR_ERR(result));
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700149 return result;
150}
151
152/*
153 * Try to extend this transaction for the purposes of truncation.
154 *
155 * Returns 0 if we managed to create more room. If we can't create more
156 * room, and the transaction must be restarted we return 1.
157 */
158static int try_to_extend_transaction(handle_t *handle, struct inode *inode)
159{
Mingming Cao617ba132006-10-11 01:20:53 -0700160 if (handle->h_buffer_credits > EXT4_RESERVE_TRANS_BLOCKS)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700161 return 0;
Mingming Cao617ba132006-10-11 01:20:53 -0700162 if (!ext4_journal_extend(handle, blocks_for_truncate(inode)))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700163 return 0;
164 return 1;
165}
166
167/*
168 * Restart the transaction associated with *handle. This does a commit,
169 * so before we call here everything must be consistently dirtied against
170 * this transaction.
171 */
Mingming Cao617ba132006-10-11 01:20:53 -0700172static int ext4_journal_test_restart(handle_t *handle, struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700173{
174 jbd_debug(2, "restarting handle %p\n", handle);
Mingming Cao617ba132006-10-11 01:20:53 -0700175 return ext4_journal_restart(handle, blocks_for_truncate(inode));
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700176}
177
178/*
179 * Called at the last iput() if i_nlink is zero.
180 */
Mingming Cao617ba132006-10-11 01:20:53 -0700181void ext4_delete_inode (struct inode * inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700182{
183 handle_t *handle;
184
185 truncate_inode_pages(&inode->i_data, 0);
186
187 if (is_bad_inode(inode))
188 goto no_delete;
189
190 handle = start_transaction(inode);
191 if (IS_ERR(handle)) {
192 /*
193 * If we're going to skip the normal cleanup, we still need to
194 * make sure that the in-core orphan linked list is properly
195 * cleaned up.
196 */
Mingming Cao617ba132006-10-11 01:20:53 -0700197 ext4_orphan_del(NULL, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700198 goto no_delete;
199 }
200
201 if (IS_SYNC(inode))
202 handle->h_sync = 1;
203 inode->i_size = 0;
204 if (inode->i_blocks)
Mingming Cao617ba132006-10-11 01:20:53 -0700205 ext4_truncate(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700206 /*
Mingming Cao617ba132006-10-11 01:20:53 -0700207 * Kill off the orphan record which ext4_truncate created.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700208 * AKPM: I think this can be inside the above `if'.
Mingming Cao617ba132006-10-11 01:20:53 -0700209 * Note that ext4_orphan_del() has to be able to cope with the
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700210 * deletion of a non-existent orphan - this is because we don't
Mingming Cao617ba132006-10-11 01:20:53 -0700211 * know if ext4_truncate() actually created an orphan record.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700212 * (Well, we could do this if we need to, but heck - it works)
213 */
Mingming Cao617ba132006-10-11 01:20:53 -0700214 ext4_orphan_del(handle, inode);
215 EXT4_I(inode)->i_dtime = get_seconds();
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700216
217 /*
218 * One subtle ordering requirement: if anything has gone wrong
219 * (transaction abort, IO errors, whatever), then we can still
220 * do these next steps (the fs will already have been marked as
221 * having errors), but we can't free the inode if the mark_dirty
222 * fails.
223 */
Mingming Cao617ba132006-10-11 01:20:53 -0700224 if (ext4_mark_inode_dirty(handle, inode))
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700225 /* If that failed, just do the required in-core inode clear. */
226 clear_inode(inode);
227 else
Mingming Cao617ba132006-10-11 01:20:53 -0700228 ext4_free_inode(handle, inode);
229 ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700230 return;
231no_delete:
232 clear_inode(inode); /* We must guarantee clearing of inode... */
233}
234
235typedef struct {
236 __le32 *p;
237 __le32 key;
238 struct buffer_head *bh;
239} Indirect;
240
241static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
242{
243 p->key = *(p->p = v);
244 p->bh = bh;
245}
246
247static int verify_chain(Indirect *from, Indirect *to)
248{
249 while (from <= to && from->key == *from->p)
250 from++;
251 return (from > to);
252}
253
254/**
Mingming Cao617ba132006-10-11 01:20:53 -0700255 * ext4_block_to_path - parse the block number into array of offsets
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700256 * @inode: inode in question (we are only interested in its superblock)
257 * @i_block: block number to be parsed
258 * @offsets: array to store the offsets in
259 * @boundary: set this non-zero if the referred-to block is likely to be
260 * followed (on disk) by an indirect block.
261 *
Mingming Cao617ba132006-10-11 01:20:53 -0700262 * To store the locations of file's data ext4 uses a data structure common
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700263 * for UNIX filesystems - tree of pointers anchored in the inode, with
264 * data blocks at leaves and indirect blocks in intermediate nodes.
265 * This function translates the block number into path in that tree -
266 * return value is the path length and @offsets[n] is the offset of
267 * pointer to (n+1)th node in the nth one. If @block is out of range
268 * (negative or too large) warning is printed and zero returned.
269 *
270 * Note: function doesn't find node addresses, so no IO is needed. All
271 * we need to know is the capacity of indirect blocks (taken from the
272 * inode->i_sb).
273 */
274
275/*
276 * Portability note: the last comparison (check that we fit into triple
277 * indirect block) is spelled differently, because otherwise on an
278 * architecture with 32-bit longs and 8Kb pages we might get into trouble
279 * if our filesystem had 8Kb blocks. We might use long long, but that would
280 * kill us on x86. Oh, well, at least the sign propagation does not matter -
281 * i_block would have to be negative in the very beginning, so we would not
282 * get there at all.
283 */
284
Mingming Cao617ba132006-10-11 01:20:53 -0700285static int ext4_block_to_path(struct inode *inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700286 long i_block, int offsets[4], int *boundary)
287{
Mingming Cao617ba132006-10-11 01:20:53 -0700288 int ptrs = EXT4_ADDR_PER_BLOCK(inode->i_sb);
289 int ptrs_bits = EXT4_ADDR_PER_BLOCK_BITS(inode->i_sb);
290 const long direct_blocks = EXT4_NDIR_BLOCKS,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700291 indirect_blocks = ptrs,
292 double_blocks = (1 << (ptrs_bits * 2));
293 int n = 0;
294 int final = 0;
295
296 if (i_block < 0) {
Mingming Cao617ba132006-10-11 01:20:53 -0700297 ext4_warning (inode->i_sb, "ext4_block_to_path", "block < 0");
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700298 } else if (i_block < direct_blocks) {
299 offsets[n++] = i_block;
300 final = direct_blocks;
301 } else if ( (i_block -= direct_blocks) < indirect_blocks) {
Mingming Cao617ba132006-10-11 01:20:53 -0700302 offsets[n++] = EXT4_IND_BLOCK;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700303 offsets[n++] = i_block;
304 final = ptrs;
305 } else if ((i_block -= indirect_blocks) < double_blocks) {
Mingming Cao617ba132006-10-11 01:20:53 -0700306 offsets[n++] = EXT4_DIND_BLOCK;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700307 offsets[n++] = i_block >> ptrs_bits;
308 offsets[n++] = i_block & (ptrs - 1);
309 final = ptrs;
310 } else if (((i_block -= double_blocks) >> (ptrs_bits * 2)) < ptrs) {
Mingming Cao617ba132006-10-11 01:20:53 -0700311 offsets[n++] = EXT4_TIND_BLOCK;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700312 offsets[n++] = i_block >> (ptrs_bits * 2);
313 offsets[n++] = (i_block >> ptrs_bits) & (ptrs - 1);
314 offsets[n++] = i_block & (ptrs - 1);
315 final = ptrs;
316 } else {
Mingming Cao617ba132006-10-11 01:20:53 -0700317 ext4_warning(inode->i_sb, "ext4_block_to_path", "block > big");
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700318 }
319 if (boundary)
320 *boundary = final - 1 - (i_block & (ptrs - 1));
321 return n;
322}
323
324/**
Mingming Cao617ba132006-10-11 01:20:53 -0700325 * ext4_get_branch - read the chain of indirect blocks leading to data
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700326 * @inode: inode in question
327 * @depth: depth of the chain (1 - direct pointer, etc.)
328 * @offsets: offsets of pointers in inode/indirect blocks
329 * @chain: place to store the result
330 * @err: here we store the error value
331 *
332 * Function fills the array of triples <key, p, bh> and returns %NULL
333 * if everything went OK or the pointer to the last filled triple
334 * (incomplete one) otherwise. Upon the return chain[i].key contains
335 * the number of (i+1)-th block in the chain (as it is stored in memory,
336 * i.e. little-endian 32-bit), chain[i].p contains the address of that
337 * number (it points into struct inode for i==0 and into the bh->b_data
338 * for i>0) and chain[i].bh points to the buffer_head of i-th indirect
339 * block for i>0 and NULL for i==0. In other words, it holds the block
340 * numbers of the chain, addresses they were taken from (and where we can
341 * verify that chain did not change) and buffer_heads hosting these
342 * numbers.
343 *
344 * Function stops when it stumbles upon zero pointer (absent block)
345 * (pointer to last triple returned, *@err == 0)
346 * or when it gets an IO error reading an indirect block
347 * (ditto, *@err == -EIO)
348 * or when it notices that chain had been changed while it was reading
349 * (ditto, *@err == -EAGAIN)
350 * or when it reads all @depth-1 indirect blocks successfully and finds
351 * the whole chain, all way to the data (returns %NULL, *err == 0).
352 */
Mingming Cao617ba132006-10-11 01:20:53 -0700353static Indirect *ext4_get_branch(struct inode *inode, int depth, int *offsets,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700354 Indirect chain[4], int *err)
355{
356 struct super_block *sb = inode->i_sb;
357 Indirect *p = chain;
358 struct buffer_head *bh;
359
360 *err = 0;
361 /* i_data is not going away, no lock needed */
Mingming Cao617ba132006-10-11 01:20:53 -0700362 add_chain (chain, NULL, EXT4_I(inode)->i_data + *offsets);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700363 if (!p->key)
364 goto no_block;
365 while (--depth) {
366 bh = sb_bread(sb, le32_to_cpu(p->key));
367 if (!bh)
368 goto failure;
369 /* Reader: pointers */
370 if (!verify_chain(chain, p))
371 goto changed;
372 add_chain(++p, bh, (__le32*)bh->b_data + *++offsets);
373 /* Reader: end */
374 if (!p->key)
375 goto no_block;
376 }
377 return NULL;
378
379changed:
380 brelse(bh);
381 *err = -EAGAIN;
382 goto no_block;
383failure:
384 *err = -EIO;
385no_block:
386 return p;
387}
388
389/**
Mingming Cao617ba132006-10-11 01:20:53 -0700390 * ext4_find_near - find a place for allocation with sufficient locality
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700391 * @inode: owner
392 * @ind: descriptor of indirect block.
393 *
394 * This function returns the prefered place for block allocation.
395 * It is used when heuristic for sequential allocation fails.
396 * Rules are:
397 * + if there is a block to the left of our position - allocate near it.
398 * + if pointer will live in indirect block - allocate near that block.
399 * + if pointer will live in inode - allocate in the same
400 * cylinder group.
401 *
402 * In the latter case we colour the starting block by the callers PID to
403 * prevent it from clashing with concurrent allocations for a different inode
404 * in the same block group. The PID is used here so that functionally related
405 * files will be close-by on-disk.
406 *
407 * Caller must make sure that @ind is valid and will stay that way.
408 */
Mingming Cao617ba132006-10-11 01:20:53 -0700409static ext4_fsblk_t ext4_find_near(struct inode *inode, Indirect *ind)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700410{
Mingming Cao617ba132006-10-11 01:20:53 -0700411 struct ext4_inode_info *ei = EXT4_I(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700412 __le32 *start = ind->bh ? (__le32*) ind->bh->b_data : ei->i_data;
413 __le32 *p;
Mingming Cao617ba132006-10-11 01:20:53 -0700414 ext4_fsblk_t bg_start;
415 ext4_grpblk_t colour;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700416
417 /* Try to find previous block */
418 for (p = ind->p - 1; p >= start; p--) {
419 if (*p)
420 return le32_to_cpu(*p);
421 }
422
423 /* No such thing, so let's try location of indirect block */
424 if (ind->bh)
425 return ind->bh->b_blocknr;
426
427 /*
428 * It is going to be referred to from the inode itself? OK, just put it
429 * into the same cylinder group then.
430 */
Mingming Cao617ba132006-10-11 01:20:53 -0700431 bg_start = ext4_group_first_block_no(inode->i_sb, ei->i_block_group);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700432 colour = (current->pid % 16) *
Mingming Cao617ba132006-10-11 01:20:53 -0700433 (EXT4_BLOCKS_PER_GROUP(inode->i_sb) / 16);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700434 return bg_start + colour;
435}
436
437/**
Mingming Cao617ba132006-10-11 01:20:53 -0700438 * ext4_find_goal - find a prefered place for allocation.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700439 * @inode: owner
440 * @block: block we want
441 * @chain: chain of indirect blocks
442 * @partial: pointer to the last triple within a chain
443 * @goal: place to store the result.
444 *
445 * Normally this function find the prefered place for block allocation,
446 * stores it in *@goal and returns zero.
447 */
448
Mingming Cao617ba132006-10-11 01:20:53 -0700449static ext4_fsblk_t ext4_find_goal(struct inode *inode, long block,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700450 Indirect chain[4], Indirect *partial)
451{
Mingming Cao617ba132006-10-11 01:20:53 -0700452 struct ext4_block_alloc_info *block_i;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700453
Mingming Cao617ba132006-10-11 01:20:53 -0700454 block_i = EXT4_I(inode)->i_block_alloc_info;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700455
456 /*
457 * try the heuristic for sequential allocation,
458 * failing that at least try to get decent locality.
459 */
460 if (block_i && (block == block_i->last_alloc_logical_block + 1)
461 && (block_i->last_alloc_physical_block != 0)) {
462 return block_i->last_alloc_physical_block + 1;
463 }
464
Mingming Cao617ba132006-10-11 01:20:53 -0700465 return ext4_find_near(inode, partial);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700466}
467
468/**
Mingming Cao617ba132006-10-11 01:20:53 -0700469 * ext4_blks_to_allocate: Look up the block map and count the number
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700470 * of direct blocks need to be allocated for the given branch.
471 *
472 * @branch: chain of indirect blocks
473 * @k: number of blocks need for indirect blocks
474 * @blks: number of data blocks to be mapped.
475 * @blocks_to_boundary: the offset in the indirect block
476 *
477 * return the total number of blocks to be allocate, including the
478 * direct and indirect blocks.
479 */
Mingming Cao617ba132006-10-11 01:20:53 -0700480static int ext4_blks_to_allocate(Indirect *branch, int k, unsigned long blks,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700481 int blocks_to_boundary)
482{
483 unsigned long count = 0;
484
485 /*
486 * Simple case, [t,d]Indirect block(s) has not allocated yet
487 * then it's clear blocks on that path have not allocated
488 */
489 if (k > 0) {
490 /* right now we don't handle cross boundary allocation */
491 if (blks < blocks_to_boundary + 1)
492 count += blks;
493 else
494 count += blocks_to_boundary + 1;
495 return count;
496 }
497
498 count++;
499 while (count < blks && count <= blocks_to_boundary &&
500 le32_to_cpu(*(branch[0].p + count)) == 0) {
501 count++;
502 }
503 return count;
504}
505
506/**
Mingming Cao617ba132006-10-11 01:20:53 -0700507 * ext4_alloc_blocks: multiple allocate blocks needed for a branch
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700508 * @indirect_blks: the number of blocks need to allocate for indirect
509 * blocks
510 *
511 * @new_blocks: on return it will store the new block numbers for
512 * the indirect blocks(if needed) and the first direct block,
513 * @blks: on return it will store the total number of allocated
514 * direct blocks
515 */
Mingming Cao617ba132006-10-11 01:20:53 -0700516static int ext4_alloc_blocks(handle_t *handle, struct inode *inode,
517 ext4_fsblk_t goal, int indirect_blks, int blks,
518 ext4_fsblk_t new_blocks[4], int *err)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700519{
520 int target, i;
521 unsigned long count = 0;
522 int index = 0;
Mingming Cao617ba132006-10-11 01:20:53 -0700523 ext4_fsblk_t current_block = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700524 int ret = 0;
525
526 /*
527 * Here we try to allocate the requested multiple blocks at once,
528 * on a best-effort basis.
529 * To build a branch, we should allocate blocks for
530 * the indirect blocks(if not allocated yet), and at least
531 * the first direct block of this branch. That's the
532 * minimum number of blocks need to allocate(required)
533 */
534 target = blks + indirect_blks;
535
536 while (1) {
537 count = target;
538 /* allocating blocks for indirect blocks and direct blocks */
Mingming Cao617ba132006-10-11 01:20:53 -0700539 current_block = ext4_new_blocks(handle,inode,goal,&count,err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700540 if (*err)
541 goto failed_out;
542
543 target -= count;
544 /* allocate blocks for indirect blocks */
545 while (index < indirect_blks && count) {
546 new_blocks[index++] = current_block++;
547 count--;
548 }
549
550 if (count > 0)
551 break;
552 }
553
554 /* save the new block number for the first direct block */
555 new_blocks[index] = current_block;
556
557 /* total number of blocks allocated for direct blocks */
558 ret = count;
559 *err = 0;
560 return ret;
561failed_out:
562 for (i = 0; i <index; i++)
Mingming Cao617ba132006-10-11 01:20:53 -0700563 ext4_free_blocks(handle, inode, new_blocks[i], 1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700564 return ret;
565}
566
567/**
Mingming Cao617ba132006-10-11 01:20:53 -0700568 * ext4_alloc_branch - allocate and set up a chain of blocks.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700569 * @inode: owner
570 * @indirect_blks: number of allocated indirect blocks
571 * @blks: number of allocated direct blocks
572 * @offsets: offsets (in the blocks) to store the pointers to next.
573 * @branch: place to store the chain in.
574 *
575 * This function allocates blocks, zeroes out all but the last one,
576 * links them into chain and (if we are synchronous) writes them to disk.
577 * In other words, it prepares a branch that can be spliced onto the
578 * inode. It stores the information about that chain in the branch[], in
Mingming Cao617ba132006-10-11 01:20:53 -0700579 * the same format as ext4_get_branch() would do. We are calling it after
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700580 * we had read the existing part of chain and partial points to the last
581 * triple of that (one with zero ->key). Upon the exit we have the same
Mingming Cao617ba132006-10-11 01:20:53 -0700582 * picture as after the successful ext4_get_block(), except that in one
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700583 * place chain is disconnected - *branch->p is still zero (we did not
584 * set the last link), but branch->key contains the number that should
585 * be placed into *branch->p to fill that gap.
586 *
587 * If allocation fails we free all blocks we've allocated (and forget
588 * their buffer_heads) and return the error value the from failed
Mingming Cao617ba132006-10-11 01:20:53 -0700589 * ext4_alloc_block() (normally -ENOSPC). Otherwise we set the chain
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700590 * as described above and return 0.
591 */
Mingming Cao617ba132006-10-11 01:20:53 -0700592static int ext4_alloc_branch(handle_t *handle, struct inode *inode,
593 int indirect_blks, int *blks, ext4_fsblk_t goal,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700594 int *offsets, Indirect *branch)
595{
596 int blocksize = inode->i_sb->s_blocksize;
597 int i, n = 0;
598 int err = 0;
599 struct buffer_head *bh;
600 int num;
Mingming Cao617ba132006-10-11 01:20:53 -0700601 ext4_fsblk_t new_blocks[4];
602 ext4_fsblk_t current_block;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700603
Mingming Cao617ba132006-10-11 01:20:53 -0700604 num = ext4_alloc_blocks(handle, inode, goal, indirect_blks,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700605 *blks, new_blocks, &err);
606 if (err)
607 return err;
608
609 branch[0].key = cpu_to_le32(new_blocks[0]);
610 /*
611 * metadata blocks and data blocks are allocated.
612 */
613 for (n = 1; n <= indirect_blks; n++) {
614 /*
615 * Get buffer_head for parent block, zero it out
616 * and set the pointer to new one, then send
617 * parent to disk.
618 */
619 bh = sb_getblk(inode->i_sb, new_blocks[n-1]);
620 branch[n].bh = bh;
621 lock_buffer(bh);
622 BUFFER_TRACE(bh, "call get_create_access");
Mingming Cao617ba132006-10-11 01:20:53 -0700623 err = ext4_journal_get_create_access(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700624 if (err) {
625 unlock_buffer(bh);
626 brelse(bh);
627 goto failed;
628 }
629
630 memset(bh->b_data, 0, blocksize);
631 branch[n].p = (__le32 *) bh->b_data + offsets[n];
632 branch[n].key = cpu_to_le32(new_blocks[n]);
633 *branch[n].p = branch[n].key;
634 if ( n == indirect_blks) {
635 current_block = new_blocks[n];
636 /*
637 * End of chain, update the last new metablock of
638 * the chain to point to the new allocated
639 * data blocks numbers
640 */
641 for (i=1; i < num; i++)
642 *(branch[n].p + i) = cpu_to_le32(++current_block);
643 }
644 BUFFER_TRACE(bh, "marking uptodate");
645 set_buffer_uptodate(bh);
646 unlock_buffer(bh);
647
Mingming Cao617ba132006-10-11 01:20:53 -0700648 BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
649 err = ext4_journal_dirty_metadata(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700650 if (err)
651 goto failed;
652 }
653 *blks = num;
654 return err;
655failed:
656 /* Allocation failed, free what we already allocated */
657 for (i = 1; i <= n ; i++) {
Mingming Caodab291a2006-10-11 01:21:01 -0700658 BUFFER_TRACE(branch[i].bh, "call jbd2_journal_forget");
Mingming Cao617ba132006-10-11 01:20:53 -0700659 ext4_journal_forget(handle, branch[i].bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700660 }
661 for (i = 0; i <indirect_blks; i++)
Mingming Cao617ba132006-10-11 01:20:53 -0700662 ext4_free_blocks(handle, inode, new_blocks[i], 1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700663
Mingming Cao617ba132006-10-11 01:20:53 -0700664 ext4_free_blocks(handle, inode, new_blocks[i], num);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700665
666 return err;
667}
668
669/**
Mingming Cao617ba132006-10-11 01:20:53 -0700670 * ext4_splice_branch - splice the allocated branch onto inode.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700671 * @inode: owner
672 * @block: (logical) number of block we are adding
673 * @chain: chain of indirect blocks (with a missing link - see
Mingming Cao617ba132006-10-11 01:20:53 -0700674 * ext4_alloc_branch)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700675 * @where: location of missing link
676 * @num: number of indirect blocks we are adding
677 * @blks: number of direct blocks we are adding
678 *
679 * This function fills the missing link and does all housekeeping needed in
680 * inode (->i_blocks, etc.). In case of success we end up with the full
681 * chain to new block and return 0.
682 */
Mingming Cao617ba132006-10-11 01:20:53 -0700683static int ext4_splice_branch(handle_t *handle, struct inode *inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700684 long block, Indirect *where, int num, int blks)
685{
686 int i;
687 int err = 0;
Mingming Cao617ba132006-10-11 01:20:53 -0700688 struct ext4_block_alloc_info *block_i;
689 ext4_fsblk_t current_block;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700690
Mingming Cao617ba132006-10-11 01:20:53 -0700691 block_i = EXT4_I(inode)->i_block_alloc_info;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700692 /*
693 * If we're splicing into a [td]indirect block (as opposed to the
694 * inode) then we need to get write access to the [td]indirect block
695 * before the splice.
696 */
697 if (where->bh) {
698 BUFFER_TRACE(where->bh, "get_write_access");
Mingming Cao617ba132006-10-11 01:20:53 -0700699 err = ext4_journal_get_write_access(handle, where->bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700700 if (err)
701 goto err_out;
702 }
703 /* That's it */
704
705 *where->p = where->key;
706
707 /*
708 * Update the host buffer_head or inode to point to more just allocated
709 * direct blocks blocks
710 */
711 if (num == 0 && blks > 1) {
712 current_block = le32_to_cpu(where->key) + 1;
713 for (i = 1; i < blks; i++)
714 *(where->p + i ) = cpu_to_le32(current_block++);
715 }
716
717 /*
718 * update the most recently allocated logical & physical block
719 * in i_block_alloc_info, to assist find the proper goal block for next
720 * allocation
721 */
722 if (block_i) {
723 block_i->last_alloc_logical_block = block + blks - 1;
724 block_i->last_alloc_physical_block =
725 le32_to_cpu(where[num].key) + blks - 1;
726 }
727
728 /* We are done with atomic stuff, now do the rest of housekeeping */
729
730 inode->i_ctime = CURRENT_TIME_SEC;
Mingming Cao617ba132006-10-11 01:20:53 -0700731 ext4_mark_inode_dirty(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700732
733 /* had we spliced it onto indirect block? */
734 if (where->bh) {
735 /*
736 * If we spliced it onto an indirect block, we haven't
737 * altered the inode. Note however that if it is being spliced
738 * onto an indirect block at the very end of the file (the
739 * file is growing) then we *will* alter the inode to reflect
740 * the new i_size. But that is not done here - it is done in
Mingming Cao617ba132006-10-11 01:20:53 -0700741 * generic_commit_write->__mark_inode_dirty->ext4_dirty_inode.
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700742 */
743 jbd_debug(5, "splicing indirect only\n");
Mingming Cao617ba132006-10-11 01:20:53 -0700744 BUFFER_TRACE(where->bh, "call ext4_journal_dirty_metadata");
745 err = ext4_journal_dirty_metadata(handle, where->bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700746 if (err)
747 goto err_out;
748 } else {
749 /*
750 * OK, we spliced it into the inode itself on a direct block.
751 * Inode was dirtied above.
752 */
753 jbd_debug(5, "splicing direct\n");
754 }
755 return err;
756
757err_out:
758 for (i = 1; i <= num; i++) {
Mingming Caodab291a2006-10-11 01:21:01 -0700759 BUFFER_TRACE(where[i].bh, "call jbd2_journal_forget");
Mingming Cao617ba132006-10-11 01:20:53 -0700760 ext4_journal_forget(handle, where[i].bh);
761 ext4_free_blocks(handle,inode,le32_to_cpu(where[i-1].key),1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700762 }
Mingming Cao617ba132006-10-11 01:20:53 -0700763 ext4_free_blocks(handle, inode, le32_to_cpu(where[num].key), blks);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700764
765 return err;
766}
767
768/*
769 * Allocation strategy is simple: if we have to allocate something, we will
770 * have to go the whole way to leaf. So let's do it before attaching anything
771 * to tree, set linkage between the newborn blocks, write them if sync is
772 * required, recheck the path, free and repeat if check fails, otherwise
773 * set the last missing link (that will protect us from any truncate-generated
774 * removals - all blocks on the path are immune now) and possibly force the
775 * write on the parent block.
776 * That has a nice additional property: no special recovery from the failed
777 * allocations is needed - we simply release blocks and do not touch anything
778 * reachable from inode.
779 *
780 * `handle' can be NULL if create == 0.
781 *
782 * The BKL may not be held on entry here. Be sure to take it early.
783 * return > 0, # of blocks mapped or allocated.
784 * return = 0, if plain lookup failed.
785 * return < 0, error case.
786 */
Mingming Cao617ba132006-10-11 01:20:53 -0700787int ext4_get_blocks_handle(handle_t *handle, struct inode *inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700788 sector_t iblock, unsigned long maxblocks,
789 struct buffer_head *bh_result,
790 int create, int extend_disksize)
791{
792 int err = -EIO;
793 int offsets[4];
794 Indirect chain[4];
795 Indirect *partial;
Mingming Cao617ba132006-10-11 01:20:53 -0700796 ext4_fsblk_t goal;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700797 int indirect_blks;
798 int blocks_to_boundary = 0;
799 int depth;
Mingming Cao617ba132006-10-11 01:20:53 -0700800 struct ext4_inode_info *ei = EXT4_I(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700801 int count = 0;
Mingming Cao617ba132006-10-11 01:20:53 -0700802 ext4_fsblk_t first_block = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700803
804
Alex Tomasa86c6182006-10-11 01:21:03 -0700805 J_ASSERT(!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL));
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700806 J_ASSERT(handle != NULL || create == 0);
Mingming Cao617ba132006-10-11 01:20:53 -0700807 depth = ext4_block_to_path(inode,iblock,offsets,&blocks_to_boundary);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700808
809 if (depth == 0)
810 goto out;
811
Mingming Cao617ba132006-10-11 01:20:53 -0700812 partial = ext4_get_branch(inode, depth, offsets, chain, &err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700813
814 /* Simplest case - block found, no allocation needed */
815 if (!partial) {
816 first_block = le32_to_cpu(chain[depth - 1].key);
817 clear_buffer_new(bh_result);
818 count++;
819 /*map more blocks*/
820 while (count < maxblocks && count <= blocks_to_boundary) {
Mingming Cao617ba132006-10-11 01:20:53 -0700821 ext4_fsblk_t blk;
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700822
823 if (!verify_chain(chain, partial)) {
824 /*
825 * Indirect block might be removed by
826 * truncate while we were reading it.
827 * Handling of that case: forget what we've
828 * got now. Flag the err as EAGAIN, so it
829 * will reread.
830 */
831 err = -EAGAIN;
832 count = 0;
833 break;
834 }
835 blk = le32_to_cpu(*(chain[depth-1].p + count));
836
837 if (blk == first_block + count)
838 count++;
839 else
840 break;
841 }
842 if (err != -EAGAIN)
843 goto got_it;
844 }
845
846 /* Next simple case - plain lookup or failed read of indirect block */
847 if (!create || err == -EIO)
848 goto cleanup;
849
850 mutex_lock(&ei->truncate_mutex);
851
852 /*
853 * If the indirect block is missing while we are reading
Mingming Cao617ba132006-10-11 01:20:53 -0700854 * the chain(ext4_get_branch() returns -EAGAIN err), or
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700855 * if the chain has been changed after we grab the semaphore,
856 * (either because another process truncated this branch, or
857 * another get_block allocated this branch) re-grab the chain to see if
858 * the request block has been allocated or not.
859 *
860 * Since we already block the truncate/other get_block
861 * at this point, we will have the current copy of the chain when we
862 * splice the branch into the tree.
863 */
864 if (err == -EAGAIN || !verify_chain(chain, partial)) {
865 while (partial > chain) {
866 brelse(partial->bh);
867 partial--;
868 }
Mingming Cao617ba132006-10-11 01:20:53 -0700869 partial = ext4_get_branch(inode, depth, offsets, chain, &err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700870 if (!partial) {
871 count++;
872 mutex_unlock(&ei->truncate_mutex);
873 if (err)
874 goto cleanup;
875 clear_buffer_new(bh_result);
876 goto got_it;
877 }
878 }
879
880 /*
881 * Okay, we need to do block allocation. Lazily initialize the block
882 * allocation info here if necessary
883 */
884 if (S_ISREG(inode->i_mode) && (!ei->i_block_alloc_info))
Mingming Cao617ba132006-10-11 01:20:53 -0700885 ext4_init_block_alloc_info(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700886
Mingming Cao617ba132006-10-11 01:20:53 -0700887 goal = ext4_find_goal(inode, iblock, chain, partial);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700888
889 /* the number of blocks need to allocate for [d,t]indirect blocks */
890 indirect_blks = (chain + depth) - partial - 1;
891
892 /*
893 * Next look up the indirect map to count the totoal number of
894 * direct blocks to allocate for this branch.
895 */
Mingming Cao617ba132006-10-11 01:20:53 -0700896 count = ext4_blks_to_allocate(partial, indirect_blks,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700897 maxblocks, blocks_to_boundary);
898 /*
Mingming Cao617ba132006-10-11 01:20:53 -0700899 * Block out ext4_truncate while we alter the tree
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700900 */
Mingming Cao617ba132006-10-11 01:20:53 -0700901 err = ext4_alloc_branch(handle, inode, indirect_blks, &count, goal,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700902 offsets + (partial - chain), partial);
903
904 /*
Mingming Cao617ba132006-10-11 01:20:53 -0700905 * The ext4_splice_branch call will free and forget any buffers
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700906 * on the new chain if there is a failure, but that risks using
907 * up transaction credits, especially for bitmaps where the
908 * credits cannot be returned. Can we handle this somehow? We
909 * may need to return -EAGAIN upwards in the worst case. --sct
910 */
911 if (!err)
Mingming Cao617ba132006-10-11 01:20:53 -0700912 err = ext4_splice_branch(handle, inode, iblock,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700913 partial, indirect_blks, count);
914 /*
915 * i_disksize growing is protected by truncate_mutex. Don't forget to
916 * protect it if you're about to implement concurrent
Mingming Cao617ba132006-10-11 01:20:53 -0700917 * ext4_get_block() -bzzz
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700918 */
919 if (!err && extend_disksize && inode->i_size > ei->i_disksize)
920 ei->i_disksize = inode->i_size;
921 mutex_unlock(&ei->truncate_mutex);
922 if (err)
923 goto cleanup;
924
925 set_buffer_new(bh_result);
926got_it:
927 map_bh(bh_result, inode->i_sb, le32_to_cpu(chain[depth-1].key));
928 if (count > blocks_to_boundary)
929 set_buffer_boundary(bh_result);
930 err = count;
931 /* Clean up and exit */
932 partial = chain + depth - 1; /* the whole chain */
933cleanup:
934 while (partial > chain) {
935 BUFFER_TRACE(partial->bh, "call brelse");
936 brelse(partial->bh);
937 partial--;
938 }
939 BUFFER_TRACE(bh_result, "returned");
940out:
941 return err;
942}
943
Mingming Cao617ba132006-10-11 01:20:53 -0700944#define DIO_CREDITS (EXT4_RESERVE_TRANS_BLOCKS + 32)
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700945
Mingming Cao617ba132006-10-11 01:20:53 -0700946static int ext4_get_block(struct inode *inode, sector_t iblock,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700947 struct buffer_head *bh_result, int create)
948{
949 handle_t *handle = journal_current_handle();
950 int ret = 0;
951 unsigned max_blocks = bh_result->b_size >> inode->i_blkbits;
952
953 if (!create)
954 goto get_block; /* A read */
955
956 if (max_blocks == 1)
957 goto get_block; /* A single block get */
958
959 if (handle->h_transaction->t_state == T_LOCKED) {
960 /*
961 * Huge direct-io writes can hold off commits for long
962 * periods of time. Let this commit run.
963 */
Mingming Cao617ba132006-10-11 01:20:53 -0700964 ext4_journal_stop(handle);
965 handle = ext4_journal_start(inode, DIO_CREDITS);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700966 if (IS_ERR(handle))
967 ret = PTR_ERR(handle);
968 goto get_block;
969 }
970
Mingming Cao617ba132006-10-11 01:20:53 -0700971 if (handle->h_buffer_credits <= EXT4_RESERVE_TRANS_BLOCKS) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700972 /*
973 * Getting low on buffer credits...
974 */
Mingming Cao617ba132006-10-11 01:20:53 -0700975 ret = ext4_journal_extend(handle, DIO_CREDITS);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700976 if (ret > 0) {
977 /*
978 * Couldn't extend the transaction. Start a new one.
979 */
Mingming Cao617ba132006-10-11 01:20:53 -0700980 ret = ext4_journal_restart(handle, DIO_CREDITS);
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700981 }
982 }
983
984get_block:
985 if (ret == 0) {
Alex Tomasa86c6182006-10-11 01:21:03 -0700986 ret = ext4_get_blocks_wrap(handle, inode, iblock,
Dave Kleikampac27a0e2006-10-11 01:20:50 -0700987 max_blocks, bh_result, create, 0);
988 if (ret > 0) {
989 bh_result->b_size = (ret << inode->i_blkbits);
990 ret = 0;
991 }
992 }
993 return ret;
994}
995
996/*
997 * `handle' can be NULL if create is zero
998 */
Mingming Cao617ba132006-10-11 01:20:53 -0700999struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001000 long block, int create, int *errp)
1001{
1002 struct buffer_head dummy;
1003 int fatal = 0, err;
1004
1005 J_ASSERT(handle != NULL || create == 0);
1006
1007 dummy.b_state = 0;
1008 dummy.b_blocknr = -1000;
1009 buffer_trace_init(&dummy.b_history);
Alex Tomasa86c6182006-10-11 01:21:03 -07001010 err = ext4_get_blocks_wrap(handle, inode, block, 1,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001011 &dummy, create, 1);
1012 /*
Mingming Cao617ba132006-10-11 01:20:53 -07001013 * ext4_get_blocks_handle() returns number of blocks
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001014 * mapped. 0 in case of a HOLE.
1015 */
1016 if (err > 0) {
1017 if (err > 1)
1018 WARN_ON(1);
1019 err = 0;
1020 }
1021 *errp = err;
1022 if (!err && buffer_mapped(&dummy)) {
1023 struct buffer_head *bh;
1024 bh = sb_getblk(inode->i_sb, dummy.b_blocknr);
1025 if (!bh) {
1026 *errp = -EIO;
1027 goto err;
1028 }
1029 if (buffer_new(&dummy)) {
1030 J_ASSERT(create != 0);
1031 J_ASSERT(handle != 0);
1032
1033 /*
1034 * Now that we do not always journal data, we should
1035 * keep in mind whether this should always journal the
1036 * new buffer as metadata. For now, regular file
Mingming Cao617ba132006-10-11 01:20:53 -07001037 * writes use ext4_get_block instead, so it's not a
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001038 * problem.
1039 */
1040 lock_buffer(bh);
1041 BUFFER_TRACE(bh, "call get_create_access");
Mingming Cao617ba132006-10-11 01:20:53 -07001042 fatal = ext4_journal_get_create_access(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001043 if (!fatal && !buffer_uptodate(bh)) {
1044 memset(bh->b_data,0,inode->i_sb->s_blocksize);
1045 set_buffer_uptodate(bh);
1046 }
1047 unlock_buffer(bh);
Mingming Cao617ba132006-10-11 01:20:53 -07001048 BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
1049 err = ext4_journal_dirty_metadata(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001050 if (!fatal)
1051 fatal = err;
1052 } else {
1053 BUFFER_TRACE(bh, "not a new buffer");
1054 }
1055 if (fatal) {
1056 *errp = fatal;
1057 brelse(bh);
1058 bh = NULL;
1059 }
1060 return bh;
1061 }
1062err:
1063 return NULL;
1064}
1065
Mingming Cao617ba132006-10-11 01:20:53 -07001066struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001067 int block, int create, int *err)
1068{
1069 struct buffer_head * bh;
1070
Mingming Cao617ba132006-10-11 01:20:53 -07001071 bh = ext4_getblk(handle, inode, block, create, err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001072 if (!bh)
1073 return bh;
1074 if (buffer_uptodate(bh))
1075 return bh;
1076 ll_rw_block(READ_META, 1, &bh);
1077 wait_on_buffer(bh);
1078 if (buffer_uptodate(bh))
1079 return bh;
1080 put_bh(bh);
1081 *err = -EIO;
1082 return NULL;
1083}
1084
1085static int walk_page_buffers( handle_t *handle,
1086 struct buffer_head *head,
1087 unsigned from,
1088 unsigned to,
1089 int *partial,
1090 int (*fn)( handle_t *handle,
1091 struct buffer_head *bh))
1092{
1093 struct buffer_head *bh;
1094 unsigned block_start, block_end;
1095 unsigned blocksize = head->b_size;
1096 int err, ret = 0;
1097 struct buffer_head *next;
1098
1099 for ( bh = head, block_start = 0;
1100 ret == 0 && (bh != head || !block_start);
1101 block_start = block_end, bh = next)
1102 {
1103 next = bh->b_this_page;
1104 block_end = block_start + blocksize;
1105 if (block_end <= from || block_start >= to) {
1106 if (partial && !buffer_uptodate(bh))
1107 *partial = 1;
1108 continue;
1109 }
1110 err = (*fn)(handle, bh);
1111 if (!ret)
1112 ret = err;
1113 }
1114 return ret;
1115}
1116
1117/*
1118 * To preserve ordering, it is essential that the hole instantiation and
1119 * the data write be encapsulated in a single transaction. We cannot
Mingming Cao617ba132006-10-11 01:20:53 -07001120 * close off a transaction and start a new one between the ext4_get_block()
Mingming Caodab291a2006-10-11 01:21:01 -07001121 * and the commit_write(). So doing the jbd2_journal_start at the start of
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001122 * prepare_write() is the right place.
1123 *
Mingming Cao617ba132006-10-11 01:20:53 -07001124 * Also, this function can nest inside ext4_writepage() ->
1125 * block_write_full_page(). In that case, we *know* that ext4_writepage()
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001126 * has generated enough buffer credits to do the whole page. So we won't
1127 * block on the journal in that case, which is good, because the caller may
1128 * be PF_MEMALLOC.
1129 *
Mingming Cao617ba132006-10-11 01:20:53 -07001130 * By accident, ext4 can be reentered when a transaction is open via
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001131 * quota file writes. If we were to commit the transaction while thus
1132 * reentered, there can be a deadlock - we would be holding a quota
1133 * lock, and the commit would never complete if another thread had a
1134 * transaction open and was blocking on the quota lock - a ranking
1135 * violation.
1136 *
Mingming Caodab291a2006-10-11 01:21:01 -07001137 * So what we do is to rely on the fact that jbd2_journal_stop/journal_start
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001138 * will _not_ run commit under these circumstances because handle->h_ref
1139 * is elevated. We'll still have enough credits for the tiny quotafile
1140 * write.
1141 */
1142static int do_journal_get_write_access(handle_t *handle,
1143 struct buffer_head *bh)
1144{
1145 if (!buffer_mapped(bh) || buffer_freed(bh))
1146 return 0;
Mingming Cao617ba132006-10-11 01:20:53 -07001147 return ext4_journal_get_write_access(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001148}
1149
Andrey Savochkinb46be052006-12-06 20:37:36 -08001150/*
1151 * The idea of this helper function is following:
1152 * if prepare_write has allocated some blocks, but not all of them, the
1153 * transaction must include the content of the newly allocated blocks.
1154 * This content is expected to be set to zeroes by block_prepare_write().
1155 * 2006/10/14 SAW
1156 */
1157static int ext4_prepare_failure(struct file *file, struct page *page,
1158 unsigned from, unsigned to)
1159{
1160 struct address_space *mapping;
1161 struct buffer_head *bh, *head, *next;
1162 unsigned block_start, block_end;
1163 unsigned blocksize;
1164 int ret;
1165 handle_t *handle = ext4_journal_current_handle();
1166
1167 mapping = page->mapping;
1168 if (ext4_should_writeback_data(mapping->host)) {
1169 /* optimization: no constraints about data */
1170skip:
1171 return ext4_journal_stop(handle);
1172 }
1173
1174 head = page_buffers(page);
1175 blocksize = head->b_size;
1176 for ( bh = head, block_start = 0;
1177 bh != head || !block_start;
1178 block_start = block_end, bh = next)
1179 {
1180 next = bh->b_this_page;
1181 block_end = block_start + blocksize;
1182 if (block_end <= from)
1183 continue;
1184 if (block_start >= to) {
1185 block_start = to;
1186 break;
1187 }
1188 if (!buffer_mapped(bh))
1189 /* prepare_write failed on this bh */
1190 break;
1191 if (ext4_should_journal_data(mapping->host)) {
1192 ret = do_journal_get_write_access(handle, bh);
1193 if (ret) {
1194 ext4_journal_stop(handle);
1195 return ret;
1196 }
1197 }
1198 /*
1199 * block_start here becomes the first block where the current iteration
1200 * of prepare_write failed.
1201 */
1202 }
1203 if (block_start <= from)
1204 goto skip;
1205
1206 /* commit allocated and zeroed buffers */
1207 return mapping->a_ops->commit_write(file, page, from, block_start);
1208}
1209
Mingming Cao617ba132006-10-11 01:20:53 -07001210static int ext4_prepare_write(struct file *file, struct page *page,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001211 unsigned from, unsigned to)
1212{
1213 struct inode *inode = page->mapping->host;
Andrey Savochkinb46be052006-12-06 20:37:36 -08001214 int ret, ret2;
1215 int needed_blocks = ext4_writepage_trans_blocks(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001216 handle_t *handle;
1217 int retries = 0;
1218
1219retry:
Mingming Cao617ba132006-10-11 01:20:53 -07001220 handle = ext4_journal_start(inode, needed_blocks);
Andrey Savochkinb46be052006-12-06 20:37:36 -08001221 if (IS_ERR(handle))
1222 return PTR_ERR(handle);
Mingming Cao617ba132006-10-11 01:20:53 -07001223 if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
1224 ret = nobh_prepare_write(page, from, to, ext4_get_block);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001225 else
Mingming Cao617ba132006-10-11 01:20:53 -07001226 ret = block_prepare_write(page, from, to, ext4_get_block);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001227 if (ret)
Andrey Savochkinb46be052006-12-06 20:37:36 -08001228 goto failure;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001229
Mingming Cao617ba132006-10-11 01:20:53 -07001230 if (ext4_should_journal_data(inode)) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001231 ret = walk_page_buffers(handle, page_buffers(page),
1232 from, to, NULL, do_journal_get_write_access);
Andrey Savochkinb46be052006-12-06 20:37:36 -08001233 if (ret)
1234 /* fatal error, just put the handle and return */
Randy Dunlap01a732e2006-12-08 02:35:52 -08001235 ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001236 }
Andrey Savochkinb46be052006-12-06 20:37:36 -08001237 return ret;
1238
1239failure:
1240 ret2 = ext4_prepare_failure(file, page, from, to);
1241 if (ret2 < 0)
1242 return ret2;
Mingming Cao617ba132006-10-11 01:20:53 -07001243 if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001244 goto retry;
Andrey Savochkinb46be052006-12-06 20:37:36 -08001245 /* retry number exceeded, or other error like -EDQUOT */
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001246 return ret;
1247}
1248
Mingming Cao617ba132006-10-11 01:20:53 -07001249int ext4_journal_dirty_data(handle_t *handle, struct buffer_head *bh)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001250{
Mingming Caodab291a2006-10-11 01:21:01 -07001251 int err = jbd2_journal_dirty_data(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001252 if (err)
Mingming Cao617ba132006-10-11 01:20:53 -07001253 ext4_journal_abort_handle(__FUNCTION__, __FUNCTION__,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001254 bh, handle,err);
1255 return err;
1256}
1257
1258/* For commit_write() in data=journal mode */
1259static int commit_write_fn(handle_t *handle, struct buffer_head *bh)
1260{
1261 if (!buffer_mapped(bh) || buffer_freed(bh))
1262 return 0;
1263 set_buffer_uptodate(bh);
Mingming Cao617ba132006-10-11 01:20:53 -07001264 return ext4_journal_dirty_metadata(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001265}
1266
1267/*
1268 * We need to pick up the new inode size which generic_commit_write gave us
1269 * `file' can be NULL - eg, when called from page_symlink().
1270 *
Mingming Cao617ba132006-10-11 01:20:53 -07001271 * ext4 never places buffers on inode->i_mapping->private_list. metadata
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001272 * buffers are managed internally.
1273 */
Mingming Cao617ba132006-10-11 01:20:53 -07001274static int ext4_ordered_commit_write(struct file *file, struct page *page,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001275 unsigned from, unsigned to)
1276{
Mingming Cao617ba132006-10-11 01:20:53 -07001277 handle_t *handle = ext4_journal_current_handle();
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001278 struct inode *inode = page->mapping->host;
1279 int ret = 0, ret2;
1280
1281 ret = walk_page_buffers(handle, page_buffers(page),
Mingming Cao617ba132006-10-11 01:20:53 -07001282 from, to, NULL, ext4_journal_dirty_data);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001283
1284 if (ret == 0) {
1285 /*
1286 * generic_commit_write() will run mark_inode_dirty() if i_size
1287 * changes. So let's piggyback the i_disksize mark_inode_dirty
1288 * into that.
1289 */
1290 loff_t new_i_size;
1291
1292 new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
Mingming Cao617ba132006-10-11 01:20:53 -07001293 if (new_i_size > EXT4_I(inode)->i_disksize)
1294 EXT4_I(inode)->i_disksize = new_i_size;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001295 ret = generic_commit_write(file, page, from, to);
1296 }
Mingming Cao617ba132006-10-11 01:20:53 -07001297 ret2 = ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001298 if (!ret)
1299 ret = ret2;
1300 return ret;
1301}
1302
Mingming Cao617ba132006-10-11 01:20:53 -07001303static int ext4_writeback_commit_write(struct file *file, struct page *page,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001304 unsigned from, unsigned to)
1305{
Mingming Cao617ba132006-10-11 01:20:53 -07001306 handle_t *handle = ext4_journal_current_handle();
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001307 struct inode *inode = page->mapping->host;
1308 int ret = 0, ret2;
1309 loff_t new_i_size;
1310
1311 new_i_size = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
Mingming Cao617ba132006-10-11 01:20:53 -07001312 if (new_i_size > EXT4_I(inode)->i_disksize)
1313 EXT4_I(inode)->i_disksize = new_i_size;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001314
Mingming Cao617ba132006-10-11 01:20:53 -07001315 if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001316 ret = nobh_commit_write(file, page, from, to);
1317 else
1318 ret = generic_commit_write(file, page, from, to);
1319
Mingming Cao617ba132006-10-11 01:20:53 -07001320 ret2 = ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001321 if (!ret)
1322 ret = ret2;
1323 return ret;
1324}
1325
Mingming Cao617ba132006-10-11 01:20:53 -07001326static int ext4_journalled_commit_write(struct file *file,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001327 struct page *page, unsigned from, unsigned to)
1328{
Mingming Cao617ba132006-10-11 01:20:53 -07001329 handle_t *handle = ext4_journal_current_handle();
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001330 struct inode *inode = page->mapping->host;
1331 int ret = 0, ret2;
1332 int partial = 0;
1333 loff_t pos;
1334
1335 /*
1336 * Here we duplicate the generic_commit_write() functionality
1337 */
1338 pos = ((loff_t)page->index << PAGE_CACHE_SHIFT) + to;
1339
1340 ret = walk_page_buffers(handle, page_buffers(page), from,
1341 to, &partial, commit_write_fn);
1342 if (!partial)
1343 SetPageUptodate(page);
1344 if (pos > inode->i_size)
1345 i_size_write(inode, pos);
Mingming Cao617ba132006-10-11 01:20:53 -07001346 EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
1347 if (inode->i_size > EXT4_I(inode)->i_disksize) {
1348 EXT4_I(inode)->i_disksize = inode->i_size;
1349 ret2 = ext4_mark_inode_dirty(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001350 if (!ret)
1351 ret = ret2;
1352 }
Mingming Cao617ba132006-10-11 01:20:53 -07001353 ret2 = ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001354 if (!ret)
1355 ret = ret2;
1356 return ret;
1357}
1358
1359/*
1360 * bmap() is special. It gets used by applications such as lilo and by
1361 * the swapper to find the on-disk block of a specific piece of data.
1362 *
1363 * Naturally, this is dangerous if the block concerned is still in the
Mingming Cao617ba132006-10-11 01:20:53 -07001364 * journal. If somebody makes a swapfile on an ext4 data-journaling
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001365 * filesystem and enables swap, then they may get a nasty shock when the
1366 * data getting swapped to that swapfile suddenly gets overwritten by
1367 * the original zero's written out previously to the journal and
1368 * awaiting writeback in the kernel's buffer cache.
1369 *
1370 * So, if we see any bmap calls here on a modified, data-journaled file,
1371 * take extra steps to flush any blocks which might be in the cache.
1372 */
Mingming Cao617ba132006-10-11 01:20:53 -07001373static sector_t ext4_bmap(struct address_space *mapping, sector_t block)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001374{
1375 struct inode *inode = mapping->host;
1376 journal_t *journal;
1377 int err;
1378
Mingming Cao617ba132006-10-11 01:20:53 -07001379 if (EXT4_I(inode)->i_state & EXT4_STATE_JDATA) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001380 /*
1381 * This is a REALLY heavyweight approach, but the use of
1382 * bmap on dirty files is expected to be extremely rare:
1383 * only if we run lilo or swapon on a freshly made file
1384 * do we expect this to happen.
1385 *
1386 * (bmap requires CAP_SYS_RAWIO so this does not
1387 * represent an unprivileged user DOS attack --- we'd be
1388 * in trouble if mortal users could trigger this path at
1389 * will.)
1390 *
Mingming Cao617ba132006-10-11 01:20:53 -07001391 * NB. EXT4_STATE_JDATA is not set on files other than
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001392 * regular files. If somebody wants to bmap a directory
1393 * or symlink and gets confused because the buffer
1394 * hasn't yet been flushed to disk, they deserve
1395 * everything they get.
1396 */
1397
Mingming Cao617ba132006-10-11 01:20:53 -07001398 EXT4_I(inode)->i_state &= ~EXT4_STATE_JDATA;
1399 journal = EXT4_JOURNAL(inode);
Mingming Caodab291a2006-10-11 01:21:01 -07001400 jbd2_journal_lock_updates(journal);
1401 err = jbd2_journal_flush(journal);
1402 jbd2_journal_unlock_updates(journal);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001403
1404 if (err)
1405 return 0;
1406 }
1407
Mingming Cao617ba132006-10-11 01:20:53 -07001408 return generic_block_bmap(mapping,block,ext4_get_block);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001409}
1410
1411static int bget_one(handle_t *handle, struct buffer_head *bh)
1412{
1413 get_bh(bh);
1414 return 0;
1415}
1416
1417static int bput_one(handle_t *handle, struct buffer_head *bh)
1418{
1419 put_bh(bh);
1420 return 0;
1421}
1422
Mingming Caodab291a2006-10-11 01:21:01 -07001423static int jbd2_journal_dirty_data_fn(handle_t *handle, struct buffer_head *bh)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001424{
1425 if (buffer_mapped(bh))
Mingming Cao617ba132006-10-11 01:20:53 -07001426 return ext4_journal_dirty_data(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001427 return 0;
1428}
1429
1430/*
1431 * Note that we always start a transaction even if we're not journalling
1432 * data. This is to preserve ordering: any hole instantiation within
Mingming Cao617ba132006-10-11 01:20:53 -07001433 * __block_write_full_page -> ext4_get_block() should be journalled
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001434 * along with the data so we don't crash and then get metadata which
1435 * refers to old data.
1436 *
1437 * In all journalling modes block_write_full_page() will start the I/O.
1438 *
1439 * Problem:
1440 *
Mingming Cao617ba132006-10-11 01:20:53 -07001441 * ext4_writepage() -> kmalloc() -> __alloc_pages() -> page_launder() ->
1442 * ext4_writepage()
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001443 *
1444 * Similar for:
1445 *
Mingming Cao617ba132006-10-11 01:20:53 -07001446 * ext4_file_write() -> generic_file_write() -> __alloc_pages() -> ...
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001447 *
Mingming Cao617ba132006-10-11 01:20:53 -07001448 * Same applies to ext4_get_block(). We will deadlock on various things like
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001449 * lock_journal and i_truncate_mutex.
1450 *
1451 * Setting PF_MEMALLOC here doesn't work - too many internal memory
1452 * allocations fail.
1453 *
1454 * 16May01: If we're reentered then journal_current_handle() will be
1455 * non-zero. We simply *return*.
1456 *
1457 * 1 July 2001: @@@ FIXME:
1458 * In journalled data mode, a data buffer may be metadata against the
1459 * current transaction. But the same file is part of a shared mapping
1460 * and someone does a writepage() on it.
1461 *
1462 * We will move the buffer onto the async_data list, but *after* it has
1463 * been dirtied. So there's a small window where we have dirty data on
1464 * BJ_Metadata.
1465 *
1466 * Note that this only applies to the last partial page in the file. The
1467 * bit which block_write_full_page() uses prepare/commit for. (That's
1468 * broken code anyway: it's wrong for msync()).
1469 *
1470 * It's a rare case: affects the final partial page, for journalled data
1471 * where the file is subject to bith write() and writepage() in the same
1472 * transction. To fix it we'll need a custom block_write_full_page().
1473 * We'll probably need that anyway for journalling writepage() output.
1474 *
1475 * We don't honour synchronous mounts for writepage(). That would be
1476 * disastrous. Any write() or metadata operation will sync the fs for
1477 * us.
1478 *
1479 * AKPM2: if all the page's buffers are mapped to disk and !data=journal,
1480 * we don't need to open a transaction here.
1481 */
Mingming Cao617ba132006-10-11 01:20:53 -07001482static int ext4_ordered_writepage(struct page *page,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001483 struct writeback_control *wbc)
1484{
1485 struct inode *inode = page->mapping->host;
1486 struct buffer_head *page_bufs;
1487 handle_t *handle = NULL;
1488 int ret = 0;
1489 int err;
1490
1491 J_ASSERT(PageLocked(page));
1492
1493 /*
1494 * We give up here if we're reentered, because it might be for a
1495 * different filesystem.
1496 */
Mingming Cao617ba132006-10-11 01:20:53 -07001497 if (ext4_journal_current_handle())
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001498 goto out_fail;
1499
Mingming Cao617ba132006-10-11 01:20:53 -07001500 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001501
1502 if (IS_ERR(handle)) {
1503 ret = PTR_ERR(handle);
1504 goto out_fail;
1505 }
1506
1507 if (!page_has_buffers(page)) {
1508 create_empty_buffers(page, inode->i_sb->s_blocksize,
1509 (1 << BH_Dirty)|(1 << BH_Uptodate));
1510 }
1511 page_bufs = page_buffers(page);
1512 walk_page_buffers(handle, page_bufs, 0,
1513 PAGE_CACHE_SIZE, NULL, bget_one);
1514
Mingming Cao617ba132006-10-11 01:20:53 -07001515 ret = block_write_full_page(page, ext4_get_block, wbc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001516
1517 /*
1518 * The page can become unlocked at any point now, and
1519 * truncate can then come in and change things. So we
1520 * can't touch *page from now on. But *page_bufs is
1521 * safe due to elevated refcount.
1522 */
1523
1524 /*
1525 * And attach them to the current transaction. But only if
1526 * block_write_full_page() succeeded. Otherwise they are unmapped,
1527 * and generally junk.
1528 */
1529 if (ret == 0) {
1530 err = walk_page_buffers(handle, page_bufs, 0, PAGE_CACHE_SIZE,
Mingming Caodab291a2006-10-11 01:21:01 -07001531 NULL, jbd2_journal_dirty_data_fn);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001532 if (!ret)
1533 ret = err;
1534 }
1535 walk_page_buffers(handle, page_bufs, 0,
1536 PAGE_CACHE_SIZE, NULL, bput_one);
Mingming Cao617ba132006-10-11 01:20:53 -07001537 err = ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001538 if (!ret)
1539 ret = err;
1540 return ret;
1541
1542out_fail:
1543 redirty_page_for_writepage(wbc, page);
1544 unlock_page(page);
1545 return ret;
1546}
1547
Mingming Cao617ba132006-10-11 01:20:53 -07001548static int ext4_writeback_writepage(struct page *page,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001549 struct writeback_control *wbc)
1550{
1551 struct inode *inode = page->mapping->host;
1552 handle_t *handle = NULL;
1553 int ret = 0;
1554 int err;
1555
Mingming Cao617ba132006-10-11 01:20:53 -07001556 if (ext4_journal_current_handle())
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001557 goto out_fail;
1558
Mingming Cao617ba132006-10-11 01:20:53 -07001559 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001560 if (IS_ERR(handle)) {
1561 ret = PTR_ERR(handle);
1562 goto out_fail;
1563 }
1564
Mingming Cao617ba132006-10-11 01:20:53 -07001565 if (test_opt(inode->i_sb, NOBH) && ext4_should_writeback_data(inode))
1566 ret = nobh_writepage(page, ext4_get_block, wbc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001567 else
Mingming Cao617ba132006-10-11 01:20:53 -07001568 ret = block_write_full_page(page, ext4_get_block, wbc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001569
Mingming Cao617ba132006-10-11 01:20:53 -07001570 err = ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001571 if (!ret)
1572 ret = err;
1573 return ret;
1574
1575out_fail:
1576 redirty_page_for_writepage(wbc, page);
1577 unlock_page(page);
1578 return ret;
1579}
1580
Mingming Cao617ba132006-10-11 01:20:53 -07001581static int ext4_journalled_writepage(struct page *page,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001582 struct writeback_control *wbc)
1583{
1584 struct inode *inode = page->mapping->host;
1585 handle_t *handle = NULL;
1586 int ret = 0;
1587 int err;
1588
Mingming Cao617ba132006-10-11 01:20:53 -07001589 if (ext4_journal_current_handle())
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001590 goto no_write;
1591
Mingming Cao617ba132006-10-11 01:20:53 -07001592 handle = ext4_journal_start(inode, ext4_writepage_trans_blocks(inode));
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001593 if (IS_ERR(handle)) {
1594 ret = PTR_ERR(handle);
1595 goto no_write;
1596 }
1597
1598 if (!page_has_buffers(page) || PageChecked(page)) {
1599 /*
1600 * It's mmapped pagecache. Add buffers and journal it. There
1601 * doesn't seem much point in redirtying the page here.
1602 */
1603 ClearPageChecked(page);
1604 ret = block_prepare_write(page, 0, PAGE_CACHE_SIZE,
Mingming Cao617ba132006-10-11 01:20:53 -07001605 ext4_get_block);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001606 if (ret != 0) {
Mingming Cao617ba132006-10-11 01:20:53 -07001607 ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001608 goto out_unlock;
1609 }
1610 ret = walk_page_buffers(handle, page_buffers(page), 0,
1611 PAGE_CACHE_SIZE, NULL, do_journal_get_write_access);
1612
1613 err = walk_page_buffers(handle, page_buffers(page), 0,
1614 PAGE_CACHE_SIZE, NULL, commit_write_fn);
1615 if (ret == 0)
1616 ret = err;
Mingming Cao617ba132006-10-11 01:20:53 -07001617 EXT4_I(inode)->i_state |= EXT4_STATE_JDATA;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001618 unlock_page(page);
1619 } else {
1620 /*
1621 * It may be a page full of checkpoint-mode buffers. We don't
1622 * really know unless we go poke around in the buffer_heads.
1623 * But block_write_full_page will do the right thing.
1624 */
Mingming Cao617ba132006-10-11 01:20:53 -07001625 ret = block_write_full_page(page, ext4_get_block, wbc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001626 }
Mingming Cao617ba132006-10-11 01:20:53 -07001627 err = ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001628 if (!ret)
1629 ret = err;
1630out:
1631 return ret;
1632
1633no_write:
1634 redirty_page_for_writepage(wbc, page);
1635out_unlock:
1636 unlock_page(page);
1637 goto out;
1638}
1639
Mingming Cao617ba132006-10-11 01:20:53 -07001640static int ext4_readpage(struct file *file, struct page *page)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001641{
Mingming Cao617ba132006-10-11 01:20:53 -07001642 return mpage_readpage(page, ext4_get_block);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001643}
1644
1645static int
Mingming Cao617ba132006-10-11 01:20:53 -07001646ext4_readpages(struct file *file, struct address_space *mapping,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001647 struct list_head *pages, unsigned nr_pages)
1648{
Mingming Cao617ba132006-10-11 01:20:53 -07001649 return mpage_readpages(mapping, pages, nr_pages, ext4_get_block);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001650}
1651
Mingming Cao617ba132006-10-11 01:20:53 -07001652static void ext4_invalidatepage(struct page *page, unsigned long offset)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001653{
Mingming Cao617ba132006-10-11 01:20:53 -07001654 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001655
1656 /*
1657 * If it's a full truncate we just forget about the pending dirtying
1658 */
1659 if (offset == 0)
1660 ClearPageChecked(page);
1661
Mingming Caodab291a2006-10-11 01:21:01 -07001662 jbd2_journal_invalidatepage(journal, page, offset);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001663}
1664
Mingming Cao617ba132006-10-11 01:20:53 -07001665static int ext4_releasepage(struct page *page, gfp_t wait)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001666{
Mingming Cao617ba132006-10-11 01:20:53 -07001667 journal_t *journal = EXT4_JOURNAL(page->mapping->host);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001668
1669 WARN_ON(PageChecked(page));
1670 if (!page_has_buffers(page))
1671 return 0;
Mingming Caodab291a2006-10-11 01:21:01 -07001672 return jbd2_journal_try_to_free_buffers(journal, page, wait);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001673}
1674
1675/*
1676 * If the O_DIRECT write will extend the file then add this inode to the
1677 * orphan list. So recovery will truncate it back to the original size
1678 * if the machine crashes during the write.
1679 *
1680 * If the O_DIRECT write is intantiating holes inside i_size and the machine
1681 * crashes then stale disk data _may_ be exposed inside the file.
1682 */
Mingming Cao617ba132006-10-11 01:20:53 -07001683static ssize_t ext4_direct_IO(int rw, struct kiocb *iocb,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001684 const struct iovec *iov, loff_t offset,
1685 unsigned long nr_segs)
1686{
1687 struct file *file = iocb->ki_filp;
1688 struct inode *inode = file->f_mapping->host;
Mingming Cao617ba132006-10-11 01:20:53 -07001689 struct ext4_inode_info *ei = EXT4_I(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001690 handle_t *handle = NULL;
1691 ssize_t ret;
1692 int orphan = 0;
1693 size_t count = iov_length(iov, nr_segs);
1694
1695 if (rw == WRITE) {
1696 loff_t final_size = offset + count;
1697
Mingming Cao617ba132006-10-11 01:20:53 -07001698 handle = ext4_journal_start(inode, DIO_CREDITS);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001699 if (IS_ERR(handle)) {
1700 ret = PTR_ERR(handle);
1701 goto out;
1702 }
1703 if (final_size > inode->i_size) {
Mingming Cao617ba132006-10-11 01:20:53 -07001704 ret = ext4_orphan_add(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001705 if (ret)
1706 goto out_stop;
1707 orphan = 1;
1708 ei->i_disksize = inode->i_size;
1709 }
1710 }
1711
1712 ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
1713 offset, nr_segs,
Mingming Cao617ba132006-10-11 01:20:53 -07001714 ext4_get_block, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001715
1716 /*
Mingming Cao617ba132006-10-11 01:20:53 -07001717 * Reacquire the handle: ext4_get_block() can restart the transaction
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001718 */
1719 handle = journal_current_handle();
1720
1721out_stop:
1722 if (handle) {
1723 int err;
1724
1725 if (orphan && inode->i_nlink)
Mingming Cao617ba132006-10-11 01:20:53 -07001726 ext4_orphan_del(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001727 if (orphan && ret > 0) {
1728 loff_t end = offset + ret;
1729 if (end > inode->i_size) {
1730 ei->i_disksize = end;
1731 i_size_write(inode, end);
1732 /*
1733 * We're going to return a positive `ret'
1734 * here due to non-zero-length I/O, so there's
1735 * no way of reporting error returns from
Mingming Cao617ba132006-10-11 01:20:53 -07001736 * ext4_mark_inode_dirty() to userspace. So
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001737 * ignore it.
1738 */
Mingming Cao617ba132006-10-11 01:20:53 -07001739 ext4_mark_inode_dirty(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001740 }
1741 }
Mingming Cao617ba132006-10-11 01:20:53 -07001742 err = ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001743 if (ret == 0)
1744 ret = err;
1745 }
1746out:
1747 return ret;
1748}
1749
1750/*
Mingming Cao617ba132006-10-11 01:20:53 -07001751 * Pages can be marked dirty completely asynchronously from ext4's journalling
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001752 * activity. By filemap_sync_pte(), try_to_unmap_one(), etc. We cannot do
1753 * much here because ->set_page_dirty is called under VFS locks. The page is
1754 * not necessarily locked.
1755 *
1756 * We cannot just dirty the page and leave attached buffers clean, because the
1757 * buffers' dirty state is "definitive". We cannot just set the buffers dirty
1758 * or jbddirty because all the journalling code will explode.
1759 *
1760 * So what we do is to mark the page "pending dirty" and next time writepage
1761 * is called, propagate that into the buffers appropriately.
1762 */
Mingming Cao617ba132006-10-11 01:20:53 -07001763static int ext4_journalled_set_page_dirty(struct page *page)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001764{
1765 SetPageChecked(page);
1766 return __set_page_dirty_nobuffers(page);
1767}
1768
Mingming Cao617ba132006-10-11 01:20:53 -07001769static const struct address_space_operations ext4_ordered_aops = {
1770 .readpage = ext4_readpage,
1771 .readpages = ext4_readpages,
1772 .writepage = ext4_ordered_writepage,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001773 .sync_page = block_sync_page,
Mingming Cao617ba132006-10-11 01:20:53 -07001774 .prepare_write = ext4_prepare_write,
1775 .commit_write = ext4_ordered_commit_write,
1776 .bmap = ext4_bmap,
1777 .invalidatepage = ext4_invalidatepage,
1778 .releasepage = ext4_releasepage,
1779 .direct_IO = ext4_direct_IO,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001780 .migratepage = buffer_migrate_page,
1781};
1782
Mingming Cao617ba132006-10-11 01:20:53 -07001783static const struct address_space_operations ext4_writeback_aops = {
1784 .readpage = ext4_readpage,
1785 .readpages = ext4_readpages,
1786 .writepage = ext4_writeback_writepage,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001787 .sync_page = block_sync_page,
Mingming Cao617ba132006-10-11 01:20:53 -07001788 .prepare_write = ext4_prepare_write,
1789 .commit_write = ext4_writeback_commit_write,
1790 .bmap = ext4_bmap,
1791 .invalidatepage = ext4_invalidatepage,
1792 .releasepage = ext4_releasepage,
1793 .direct_IO = ext4_direct_IO,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001794 .migratepage = buffer_migrate_page,
1795};
1796
Mingming Cao617ba132006-10-11 01:20:53 -07001797static const struct address_space_operations ext4_journalled_aops = {
1798 .readpage = ext4_readpage,
1799 .readpages = ext4_readpages,
1800 .writepage = ext4_journalled_writepage,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001801 .sync_page = block_sync_page,
Mingming Cao617ba132006-10-11 01:20:53 -07001802 .prepare_write = ext4_prepare_write,
1803 .commit_write = ext4_journalled_commit_write,
1804 .set_page_dirty = ext4_journalled_set_page_dirty,
1805 .bmap = ext4_bmap,
1806 .invalidatepage = ext4_invalidatepage,
1807 .releasepage = ext4_releasepage,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001808};
1809
Mingming Cao617ba132006-10-11 01:20:53 -07001810void ext4_set_aops(struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001811{
Mingming Cao617ba132006-10-11 01:20:53 -07001812 if (ext4_should_order_data(inode))
1813 inode->i_mapping->a_ops = &ext4_ordered_aops;
1814 else if (ext4_should_writeback_data(inode))
1815 inode->i_mapping->a_ops = &ext4_writeback_aops;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001816 else
Mingming Cao617ba132006-10-11 01:20:53 -07001817 inode->i_mapping->a_ops = &ext4_journalled_aops;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001818}
1819
1820/*
Mingming Cao617ba132006-10-11 01:20:53 -07001821 * ext4_block_truncate_page() zeroes out a mapping from file offset `from'
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001822 * up to the end of the block which corresponds to `from'.
1823 * This required during truncate. We need to physically zero the tail end
1824 * of that block so it doesn't yield old data if the file is later grown.
1825 */
Alex Tomasa86c6182006-10-11 01:21:03 -07001826int ext4_block_truncate_page(handle_t *handle, struct page *page,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001827 struct address_space *mapping, loff_t from)
1828{
Mingming Cao617ba132006-10-11 01:20:53 -07001829 ext4_fsblk_t index = from >> PAGE_CACHE_SHIFT;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001830 unsigned offset = from & (PAGE_CACHE_SIZE-1);
1831 unsigned blocksize, iblock, length, pos;
1832 struct inode *inode = mapping->host;
1833 struct buffer_head *bh;
1834 int err = 0;
1835 void *kaddr;
1836
1837 blocksize = inode->i_sb->s_blocksize;
1838 length = blocksize - (offset & (blocksize - 1));
1839 iblock = index << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1840
1841 /*
1842 * For "nobh" option, we can only work if we don't need to
1843 * read-in the page - otherwise we create buffers to do the IO.
1844 */
1845 if (!page_has_buffers(page) && test_opt(inode->i_sb, NOBH) &&
Mingming Cao617ba132006-10-11 01:20:53 -07001846 ext4_should_writeback_data(inode) && PageUptodate(page)) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001847 kaddr = kmap_atomic(page, KM_USER0);
1848 memset(kaddr + offset, 0, length);
1849 flush_dcache_page(page);
1850 kunmap_atomic(kaddr, KM_USER0);
1851 set_page_dirty(page);
1852 goto unlock;
1853 }
1854
1855 if (!page_has_buffers(page))
1856 create_empty_buffers(page, blocksize, 0);
1857
1858 /* Find the buffer that contains "offset" */
1859 bh = page_buffers(page);
1860 pos = blocksize;
1861 while (offset >= pos) {
1862 bh = bh->b_this_page;
1863 iblock++;
1864 pos += blocksize;
1865 }
1866
1867 err = 0;
1868 if (buffer_freed(bh)) {
1869 BUFFER_TRACE(bh, "freed: skip");
1870 goto unlock;
1871 }
1872
1873 if (!buffer_mapped(bh)) {
1874 BUFFER_TRACE(bh, "unmapped");
Mingming Cao617ba132006-10-11 01:20:53 -07001875 ext4_get_block(inode, iblock, bh, 0);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001876 /* unmapped? It's a hole - nothing to do */
1877 if (!buffer_mapped(bh)) {
1878 BUFFER_TRACE(bh, "still unmapped");
1879 goto unlock;
1880 }
1881 }
1882
1883 /* Ok, it's mapped. Make sure it's up-to-date */
1884 if (PageUptodate(page))
1885 set_buffer_uptodate(bh);
1886
1887 if (!buffer_uptodate(bh)) {
1888 err = -EIO;
1889 ll_rw_block(READ, 1, &bh);
1890 wait_on_buffer(bh);
1891 /* Uhhuh. Read error. Complain and punt. */
1892 if (!buffer_uptodate(bh))
1893 goto unlock;
1894 }
1895
Mingming Cao617ba132006-10-11 01:20:53 -07001896 if (ext4_should_journal_data(inode)) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001897 BUFFER_TRACE(bh, "get write access");
Mingming Cao617ba132006-10-11 01:20:53 -07001898 err = ext4_journal_get_write_access(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001899 if (err)
1900 goto unlock;
1901 }
1902
1903 kaddr = kmap_atomic(page, KM_USER0);
1904 memset(kaddr + offset, 0, length);
1905 flush_dcache_page(page);
1906 kunmap_atomic(kaddr, KM_USER0);
1907
1908 BUFFER_TRACE(bh, "zeroed end of block");
1909
1910 err = 0;
Mingming Cao617ba132006-10-11 01:20:53 -07001911 if (ext4_should_journal_data(inode)) {
1912 err = ext4_journal_dirty_metadata(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001913 } else {
Mingming Cao617ba132006-10-11 01:20:53 -07001914 if (ext4_should_order_data(inode))
1915 err = ext4_journal_dirty_data(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001916 mark_buffer_dirty(bh);
1917 }
1918
1919unlock:
1920 unlock_page(page);
1921 page_cache_release(page);
1922 return err;
1923}
1924
1925/*
1926 * Probably it should be a library function... search for first non-zero word
1927 * or memcmp with zero_page, whatever is better for particular architecture.
1928 * Linus?
1929 */
1930static inline int all_zeroes(__le32 *p, __le32 *q)
1931{
1932 while (p < q)
1933 if (*p++)
1934 return 0;
1935 return 1;
1936}
1937
1938/**
Mingming Cao617ba132006-10-11 01:20:53 -07001939 * ext4_find_shared - find the indirect blocks for partial truncation.
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001940 * @inode: inode in question
1941 * @depth: depth of the affected branch
Mingming Cao617ba132006-10-11 01:20:53 -07001942 * @offsets: offsets of pointers in that branch (see ext4_block_to_path)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001943 * @chain: place to store the pointers to partial indirect blocks
1944 * @top: place to the (detached) top of branch
1945 *
Mingming Cao617ba132006-10-11 01:20:53 -07001946 * This is a helper function used by ext4_truncate().
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001947 *
1948 * When we do truncate() we may have to clean the ends of several
1949 * indirect blocks but leave the blocks themselves alive. Block is
1950 * partially truncated if some data below the new i_size is refered
1951 * from it (and it is on the path to the first completely truncated
1952 * data block, indeed). We have to free the top of that path along
1953 * with everything to the right of the path. Since no allocation
Mingming Cao617ba132006-10-11 01:20:53 -07001954 * past the truncation point is possible until ext4_truncate()
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001955 * finishes, we may safely do the latter, but top of branch may
1956 * require special attention - pageout below the truncation point
1957 * might try to populate it.
1958 *
1959 * We atomically detach the top of branch from the tree, store the
1960 * block number of its root in *@top, pointers to buffer_heads of
1961 * partially truncated blocks - in @chain[].bh and pointers to
1962 * their last elements that should not be removed - in
1963 * @chain[].p. Return value is the pointer to last filled element
1964 * of @chain.
1965 *
1966 * The work left to caller to do the actual freeing of subtrees:
1967 * a) free the subtree starting from *@top
1968 * b) free the subtrees whose roots are stored in
1969 * (@chain[i].p+1 .. end of @chain[i].bh->b_data)
1970 * c) free the subtrees growing from the inode past the @chain[0].
1971 * (no partially truncated stuff there). */
1972
Mingming Cao617ba132006-10-11 01:20:53 -07001973static Indirect *ext4_find_shared(struct inode *inode, int depth,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001974 int offsets[4], Indirect chain[4], __le32 *top)
1975{
1976 Indirect *partial, *p;
1977 int k, err;
1978
1979 *top = 0;
1980 /* Make k index the deepest non-null offest + 1 */
1981 for (k = depth; k > 1 && !offsets[k-1]; k--)
1982 ;
Mingming Cao617ba132006-10-11 01:20:53 -07001983 partial = ext4_get_branch(inode, k, offsets, chain, &err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07001984 /* Writer: pointers */
1985 if (!partial)
1986 partial = chain + k-1;
1987 /*
1988 * If the branch acquired continuation since we've looked at it -
1989 * fine, it should all survive and (new) top doesn't belong to us.
1990 */
1991 if (!partial->key && *partial->p)
1992 /* Writer: end */
1993 goto no_top;
1994 for (p=partial; p>chain && all_zeroes((__le32*)p->bh->b_data,p->p); p--)
1995 ;
1996 /*
1997 * OK, we've found the last block that must survive. The rest of our
1998 * branch should be detached before unlocking. However, if that rest
1999 * of branch is all ours and does not grow immediately from the inode
2000 * it's easier to cheat and just decrement partial->p.
2001 */
2002 if (p == chain + k - 1 && p > chain) {
2003 p->p--;
2004 } else {
2005 *top = *p->p;
Mingming Cao617ba132006-10-11 01:20:53 -07002006 /* Nope, don't do this in ext4. Must leave the tree intact */
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002007#if 0
2008 *p->p = 0;
2009#endif
2010 }
2011 /* Writer: end */
2012
2013 while(partial > p) {
2014 brelse(partial->bh);
2015 partial--;
2016 }
2017no_top:
2018 return partial;
2019}
2020
2021/*
2022 * Zero a number of block pointers in either an inode or an indirect block.
2023 * If we restart the transaction we must again get write access to the
2024 * indirect block for further modification.
2025 *
2026 * We release `count' blocks on disk, but (last - first) may be greater
2027 * than `count' because there can be holes in there.
2028 */
Mingming Cao617ba132006-10-11 01:20:53 -07002029static void ext4_clear_blocks(handle_t *handle, struct inode *inode,
2030 struct buffer_head *bh, ext4_fsblk_t block_to_free,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002031 unsigned long count, __le32 *first, __le32 *last)
2032{
2033 __le32 *p;
2034 if (try_to_extend_transaction(handle, inode)) {
2035 if (bh) {
Mingming Cao617ba132006-10-11 01:20:53 -07002036 BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
2037 ext4_journal_dirty_metadata(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002038 }
Mingming Cao617ba132006-10-11 01:20:53 -07002039 ext4_mark_inode_dirty(handle, inode);
2040 ext4_journal_test_restart(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002041 if (bh) {
2042 BUFFER_TRACE(bh, "retaking write access");
Mingming Cao617ba132006-10-11 01:20:53 -07002043 ext4_journal_get_write_access(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002044 }
2045 }
2046
2047 /*
2048 * Any buffers which are on the journal will be in memory. We find
Mingming Caodab291a2006-10-11 01:21:01 -07002049 * them on the hash table so jbd2_journal_revoke() will run jbd2_journal_forget()
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002050 * on them. We've already detached each block from the file, so
Mingming Caodab291a2006-10-11 01:21:01 -07002051 * bforget() in jbd2_journal_forget() should be safe.
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002052 *
Mingming Caodab291a2006-10-11 01:21:01 -07002053 * AKPM: turn on bforget in jbd2_journal_forget()!!!
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002054 */
2055 for (p = first; p < last; p++) {
2056 u32 nr = le32_to_cpu(*p);
2057 if (nr) {
2058 struct buffer_head *bh;
2059
2060 *p = 0;
2061 bh = sb_find_get_block(inode->i_sb, nr);
Mingming Cao617ba132006-10-11 01:20:53 -07002062 ext4_forget(handle, 0, inode, bh, nr);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002063 }
2064 }
2065
Mingming Cao617ba132006-10-11 01:20:53 -07002066 ext4_free_blocks(handle, inode, block_to_free, count);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002067}
2068
2069/**
Mingming Cao617ba132006-10-11 01:20:53 -07002070 * ext4_free_data - free a list of data blocks
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002071 * @handle: handle for this transaction
2072 * @inode: inode we are dealing with
2073 * @this_bh: indirect buffer_head which contains *@first and *@last
2074 * @first: array of block numbers
2075 * @last: points immediately past the end of array
2076 *
2077 * We are freeing all blocks refered from that array (numbers are stored as
2078 * little-endian 32-bit) and updating @inode->i_blocks appropriately.
2079 *
2080 * We accumulate contiguous runs of blocks to free. Conveniently, if these
2081 * blocks are contiguous then releasing them at one time will only affect one
2082 * or two bitmap blocks (+ group descriptor(s) and superblock) and we won't
2083 * actually use a lot of journal space.
2084 *
2085 * @this_bh will be %NULL if @first and @last point into the inode's direct
2086 * block pointers.
2087 */
Mingming Cao617ba132006-10-11 01:20:53 -07002088static void ext4_free_data(handle_t *handle, struct inode *inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002089 struct buffer_head *this_bh,
2090 __le32 *first, __le32 *last)
2091{
Mingming Cao617ba132006-10-11 01:20:53 -07002092 ext4_fsblk_t block_to_free = 0; /* Starting block # of a run */
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002093 unsigned long count = 0; /* Number of blocks in the run */
2094 __le32 *block_to_free_p = NULL; /* Pointer into inode/ind
2095 corresponding to
2096 block_to_free */
Mingming Cao617ba132006-10-11 01:20:53 -07002097 ext4_fsblk_t nr; /* Current block # */
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002098 __le32 *p; /* Pointer into inode/ind
2099 for current block */
2100 int err;
2101
2102 if (this_bh) { /* For indirect block */
2103 BUFFER_TRACE(this_bh, "get_write_access");
Mingming Cao617ba132006-10-11 01:20:53 -07002104 err = ext4_journal_get_write_access(handle, this_bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002105 /* Important: if we can't update the indirect pointers
2106 * to the blocks, we can't free them. */
2107 if (err)
2108 return;
2109 }
2110
2111 for (p = first; p < last; p++) {
2112 nr = le32_to_cpu(*p);
2113 if (nr) {
2114 /* accumulate blocks to free if they're contiguous */
2115 if (count == 0) {
2116 block_to_free = nr;
2117 block_to_free_p = p;
2118 count = 1;
2119 } else if (nr == block_to_free + count) {
2120 count++;
2121 } else {
Mingming Cao617ba132006-10-11 01:20:53 -07002122 ext4_clear_blocks(handle, inode, this_bh,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002123 block_to_free,
2124 count, block_to_free_p, p);
2125 block_to_free = nr;
2126 block_to_free_p = p;
2127 count = 1;
2128 }
2129 }
2130 }
2131
2132 if (count > 0)
Mingming Cao617ba132006-10-11 01:20:53 -07002133 ext4_clear_blocks(handle, inode, this_bh, block_to_free,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002134 count, block_to_free_p, p);
2135
2136 if (this_bh) {
Mingming Cao617ba132006-10-11 01:20:53 -07002137 BUFFER_TRACE(this_bh, "call ext4_journal_dirty_metadata");
2138 ext4_journal_dirty_metadata(handle, this_bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002139 }
2140}
2141
2142/**
Mingming Cao617ba132006-10-11 01:20:53 -07002143 * ext4_free_branches - free an array of branches
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002144 * @handle: JBD handle for this transaction
2145 * @inode: inode we are dealing with
2146 * @parent_bh: the buffer_head which contains *@first and *@last
2147 * @first: array of block numbers
2148 * @last: pointer immediately past the end of array
2149 * @depth: depth of the branches to free
2150 *
2151 * We are freeing all blocks refered from these branches (numbers are
2152 * stored as little-endian 32-bit) and updating @inode->i_blocks
2153 * appropriately.
2154 */
Mingming Cao617ba132006-10-11 01:20:53 -07002155static void ext4_free_branches(handle_t *handle, struct inode *inode,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002156 struct buffer_head *parent_bh,
2157 __le32 *first, __le32 *last, int depth)
2158{
Mingming Cao617ba132006-10-11 01:20:53 -07002159 ext4_fsblk_t nr;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002160 __le32 *p;
2161
2162 if (is_handle_aborted(handle))
2163 return;
2164
2165 if (depth--) {
2166 struct buffer_head *bh;
Mingming Cao617ba132006-10-11 01:20:53 -07002167 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002168 p = last;
2169 while (--p >= first) {
2170 nr = le32_to_cpu(*p);
2171 if (!nr)
2172 continue; /* A hole */
2173
2174 /* Go read the buffer for the next level down */
2175 bh = sb_bread(inode->i_sb, nr);
2176
2177 /*
2178 * A read failure? Report error and clear slot
2179 * (should be rare).
2180 */
2181 if (!bh) {
Mingming Cao617ba132006-10-11 01:20:53 -07002182 ext4_error(inode->i_sb, "ext4_free_branches",
Mingming Cao2ae02102006-10-11 01:21:11 -07002183 "Read failure, inode=%lu, block=%llu",
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002184 inode->i_ino, nr);
2185 continue;
2186 }
2187
2188 /* This zaps the entire block. Bottom up. */
2189 BUFFER_TRACE(bh, "free child branches");
Mingming Cao617ba132006-10-11 01:20:53 -07002190 ext4_free_branches(handle, inode, bh,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002191 (__le32*)bh->b_data,
2192 (__le32*)bh->b_data + addr_per_block,
2193 depth);
2194
2195 /*
2196 * We've probably journalled the indirect block several
2197 * times during the truncate. But it's no longer
2198 * needed and we now drop it from the transaction via
Mingming Caodab291a2006-10-11 01:21:01 -07002199 * jbd2_journal_revoke().
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002200 *
2201 * That's easy if it's exclusively part of this
2202 * transaction. But if it's part of the committing
Mingming Caodab291a2006-10-11 01:21:01 -07002203 * transaction then jbd2_journal_forget() will simply
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002204 * brelse() it. That means that if the underlying
Mingming Cao617ba132006-10-11 01:20:53 -07002205 * block is reallocated in ext4_get_block(),
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002206 * unmap_underlying_metadata() will find this block
2207 * and will try to get rid of it. damn, damn.
2208 *
2209 * If this block has already been committed to the
2210 * journal, a revoke record will be written. And
2211 * revoke records must be emitted *before* clearing
2212 * this block's bit in the bitmaps.
2213 */
Mingming Cao617ba132006-10-11 01:20:53 -07002214 ext4_forget(handle, 1, inode, bh, bh->b_blocknr);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002215
2216 /*
2217 * Everything below this this pointer has been
2218 * released. Now let this top-of-subtree go.
2219 *
2220 * We want the freeing of this indirect block to be
2221 * atomic in the journal with the updating of the
2222 * bitmap block which owns it. So make some room in
2223 * the journal.
2224 *
2225 * We zero the parent pointer *after* freeing its
2226 * pointee in the bitmaps, so if extend_transaction()
2227 * for some reason fails to put the bitmap changes and
2228 * the release into the same transaction, recovery
2229 * will merely complain about releasing a free block,
2230 * rather than leaking blocks.
2231 */
2232 if (is_handle_aborted(handle))
2233 return;
2234 if (try_to_extend_transaction(handle, inode)) {
Mingming Cao617ba132006-10-11 01:20:53 -07002235 ext4_mark_inode_dirty(handle, inode);
2236 ext4_journal_test_restart(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002237 }
2238
Mingming Cao617ba132006-10-11 01:20:53 -07002239 ext4_free_blocks(handle, inode, nr, 1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002240
2241 if (parent_bh) {
2242 /*
2243 * The block which we have just freed is
2244 * pointed to by an indirect block: journal it
2245 */
2246 BUFFER_TRACE(parent_bh, "get_write_access");
Mingming Cao617ba132006-10-11 01:20:53 -07002247 if (!ext4_journal_get_write_access(handle,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002248 parent_bh)){
2249 *p = 0;
2250 BUFFER_TRACE(parent_bh,
Mingming Cao617ba132006-10-11 01:20:53 -07002251 "call ext4_journal_dirty_metadata");
2252 ext4_journal_dirty_metadata(handle,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002253 parent_bh);
2254 }
2255 }
2256 }
2257 } else {
2258 /* We have reached the bottom of the tree. */
2259 BUFFER_TRACE(parent_bh, "free data blocks");
Mingming Cao617ba132006-10-11 01:20:53 -07002260 ext4_free_data(handle, inode, parent_bh, first, last);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002261 }
2262}
2263
2264/*
Mingming Cao617ba132006-10-11 01:20:53 -07002265 * ext4_truncate()
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002266 *
Mingming Cao617ba132006-10-11 01:20:53 -07002267 * We block out ext4_get_block() block instantiations across the entire
2268 * transaction, and VFS/VM ensures that ext4_truncate() cannot run
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002269 * simultaneously on behalf of the same inode.
2270 *
2271 * As we work through the truncate and commmit bits of it to the journal there
2272 * is one core, guiding principle: the file's tree must always be consistent on
2273 * disk. We must be able to restart the truncate after a crash.
2274 *
2275 * The file's tree may be transiently inconsistent in memory (although it
2276 * probably isn't), but whenever we close off and commit a journal transaction,
2277 * the contents of (the filesystem + the journal) must be consistent and
2278 * restartable. It's pretty simple, really: bottom up, right to left (although
2279 * left-to-right works OK too).
2280 *
2281 * Note that at recovery time, journal replay occurs *before* the restart of
2282 * truncate against the orphan inode list.
2283 *
2284 * The committed inode has the new, desired i_size (which is the same as
Mingming Cao617ba132006-10-11 01:20:53 -07002285 * i_disksize in this case). After a crash, ext4_orphan_cleanup() will see
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002286 * that this inode's truncate did not complete and it will again call
Mingming Cao617ba132006-10-11 01:20:53 -07002287 * ext4_truncate() to have another go. So there will be instantiated blocks
2288 * to the right of the truncation point in a crashed ext4 filesystem. But
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002289 * that's fine - as long as they are linked from the inode, the post-crash
Mingming Cao617ba132006-10-11 01:20:53 -07002290 * ext4_truncate() run will find them and release them.
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002291 */
Mingming Cao617ba132006-10-11 01:20:53 -07002292void ext4_truncate(struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002293{
2294 handle_t *handle;
Mingming Cao617ba132006-10-11 01:20:53 -07002295 struct ext4_inode_info *ei = EXT4_I(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002296 __le32 *i_data = ei->i_data;
Mingming Cao617ba132006-10-11 01:20:53 -07002297 int addr_per_block = EXT4_ADDR_PER_BLOCK(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002298 struct address_space *mapping = inode->i_mapping;
2299 int offsets[4];
2300 Indirect chain[4];
2301 Indirect *partial;
2302 __le32 nr = 0;
2303 int n;
2304 long last_block;
2305 unsigned blocksize = inode->i_sb->s_blocksize;
2306 struct page *page;
2307
2308 if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
2309 S_ISLNK(inode->i_mode)))
2310 return;
Mingming Cao617ba132006-10-11 01:20:53 -07002311 if (ext4_inode_is_fast_symlink(inode))
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002312 return;
2313 if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
2314 return;
2315
2316 /*
2317 * We have to lock the EOF page here, because lock_page() nests
Mingming Caodab291a2006-10-11 01:21:01 -07002318 * outside jbd2_journal_start().
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002319 */
2320 if ((inode->i_size & (blocksize - 1)) == 0) {
2321 /* Block boundary? Nothing to do */
2322 page = NULL;
2323 } else {
2324 page = grab_cache_page(mapping,
2325 inode->i_size >> PAGE_CACHE_SHIFT);
2326 if (!page)
2327 return;
2328 }
2329
Alex Tomasa86c6182006-10-11 01:21:03 -07002330 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
2331 return ext4_ext_truncate(inode, page);
2332
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002333 handle = start_transaction(inode);
2334 if (IS_ERR(handle)) {
2335 if (page) {
2336 clear_highpage(page);
2337 flush_dcache_page(page);
2338 unlock_page(page);
2339 page_cache_release(page);
2340 }
2341 return; /* AKPM: return what? */
2342 }
2343
2344 last_block = (inode->i_size + blocksize-1)
Mingming Cao617ba132006-10-11 01:20:53 -07002345 >> EXT4_BLOCK_SIZE_BITS(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002346
2347 if (page)
Mingming Cao617ba132006-10-11 01:20:53 -07002348 ext4_block_truncate_page(handle, page, mapping, inode->i_size);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002349
Mingming Cao617ba132006-10-11 01:20:53 -07002350 n = ext4_block_to_path(inode, last_block, offsets, NULL);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002351 if (n == 0)
2352 goto out_stop; /* error */
2353
2354 /*
2355 * OK. This truncate is going to happen. We add the inode to the
2356 * orphan list, so that if this truncate spans multiple transactions,
2357 * and we crash, we will resume the truncate when the filesystem
2358 * recovers. It also marks the inode dirty, to catch the new size.
2359 *
2360 * Implication: the file must always be in a sane, consistent
2361 * truncatable state while each transaction commits.
2362 */
Mingming Cao617ba132006-10-11 01:20:53 -07002363 if (ext4_orphan_add(handle, inode))
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002364 goto out_stop;
2365
2366 /*
2367 * The orphan list entry will now protect us from any crash which
2368 * occurs before the truncate completes, so it is now safe to propagate
2369 * the new, shorter inode size (held for now in i_size) into the
2370 * on-disk inode. We do this via i_disksize, which is the value which
Mingming Cao617ba132006-10-11 01:20:53 -07002371 * ext4 *really* writes onto the disk inode.
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002372 */
2373 ei->i_disksize = inode->i_size;
2374
2375 /*
Mingming Cao617ba132006-10-11 01:20:53 -07002376 * From here we block out all ext4_get_block() callers who want to
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002377 * modify the block allocation tree.
2378 */
2379 mutex_lock(&ei->truncate_mutex);
2380
2381 if (n == 1) { /* direct blocks */
Mingming Cao617ba132006-10-11 01:20:53 -07002382 ext4_free_data(handle, inode, NULL, i_data+offsets[0],
2383 i_data + EXT4_NDIR_BLOCKS);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002384 goto do_indirects;
2385 }
2386
Mingming Cao617ba132006-10-11 01:20:53 -07002387 partial = ext4_find_shared(inode, n, offsets, chain, &nr);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002388 /* Kill the top of shared branch (not detached) */
2389 if (nr) {
2390 if (partial == chain) {
2391 /* Shared branch grows from the inode */
Mingming Cao617ba132006-10-11 01:20:53 -07002392 ext4_free_branches(handle, inode, NULL,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002393 &nr, &nr+1, (chain+n-1) - partial);
2394 *partial->p = 0;
2395 /*
2396 * We mark the inode dirty prior to restart,
2397 * and prior to stop. No need for it here.
2398 */
2399 } else {
2400 /* Shared branch grows from an indirect block */
2401 BUFFER_TRACE(partial->bh, "get_write_access");
Mingming Cao617ba132006-10-11 01:20:53 -07002402 ext4_free_branches(handle, inode, partial->bh,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002403 partial->p,
2404 partial->p+1, (chain+n-1) - partial);
2405 }
2406 }
2407 /* Clear the ends of indirect blocks on the shared branch */
2408 while (partial > chain) {
Mingming Cao617ba132006-10-11 01:20:53 -07002409 ext4_free_branches(handle, inode, partial->bh, partial->p + 1,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002410 (__le32*)partial->bh->b_data+addr_per_block,
2411 (chain+n-1) - partial);
2412 BUFFER_TRACE(partial->bh, "call brelse");
2413 brelse (partial->bh);
2414 partial--;
2415 }
2416do_indirects:
2417 /* Kill the remaining (whole) subtrees */
2418 switch (offsets[0]) {
2419 default:
Mingming Cao617ba132006-10-11 01:20:53 -07002420 nr = i_data[EXT4_IND_BLOCK];
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002421 if (nr) {
Mingming Cao617ba132006-10-11 01:20:53 -07002422 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 1);
2423 i_data[EXT4_IND_BLOCK] = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002424 }
Mingming Cao617ba132006-10-11 01:20:53 -07002425 case EXT4_IND_BLOCK:
2426 nr = i_data[EXT4_DIND_BLOCK];
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002427 if (nr) {
Mingming Cao617ba132006-10-11 01:20:53 -07002428 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 2);
2429 i_data[EXT4_DIND_BLOCK] = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002430 }
Mingming Cao617ba132006-10-11 01:20:53 -07002431 case EXT4_DIND_BLOCK:
2432 nr = i_data[EXT4_TIND_BLOCK];
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002433 if (nr) {
Mingming Cao617ba132006-10-11 01:20:53 -07002434 ext4_free_branches(handle, inode, NULL, &nr, &nr+1, 3);
2435 i_data[EXT4_TIND_BLOCK] = 0;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002436 }
Mingming Cao617ba132006-10-11 01:20:53 -07002437 case EXT4_TIND_BLOCK:
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002438 ;
2439 }
2440
Mingming Cao617ba132006-10-11 01:20:53 -07002441 ext4_discard_reservation(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002442
2443 mutex_unlock(&ei->truncate_mutex);
2444 inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
Mingming Cao617ba132006-10-11 01:20:53 -07002445 ext4_mark_inode_dirty(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002446
2447 /*
2448 * In a multi-transaction truncate, we only make the final transaction
2449 * synchronous
2450 */
2451 if (IS_SYNC(inode))
2452 handle->h_sync = 1;
2453out_stop:
2454 /*
2455 * If this was a simple ftruncate(), and the file will remain alive
2456 * then we need to clear up the orphan record which we created above.
2457 * However, if this was a real unlink then we were called by
Mingming Cao617ba132006-10-11 01:20:53 -07002458 * ext4_delete_inode(), and we allow that function to clean up the
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002459 * orphan info for us.
2460 */
2461 if (inode->i_nlink)
Mingming Cao617ba132006-10-11 01:20:53 -07002462 ext4_orphan_del(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002463
Mingming Cao617ba132006-10-11 01:20:53 -07002464 ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002465}
2466
Mingming Cao617ba132006-10-11 01:20:53 -07002467static ext4_fsblk_t ext4_get_inode_block(struct super_block *sb,
2468 unsigned long ino, struct ext4_iloc *iloc)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002469{
2470 unsigned long desc, group_desc, block_group;
2471 unsigned long offset;
Mingming Cao617ba132006-10-11 01:20:53 -07002472 ext4_fsblk_t block;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002473 struct buffer_head *bh;
Mingming Cao617ba132006-10-11 01:20:53 -07002474 struct ext4_group_desc * gdp;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002475
Mingming Cao617ba132006-10-11 01:20:53 -07002476 if (!ext4_valid_inum(sb, ino)) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002477 /*
2478 * This error is already checked for in namei.c unless we are
2479 * looking at an NFS filehandle, in which case no error
2480 * report is needed
2481 */
2482 return 0;
2483 }
2484
Mingming Cao617ba132006-10-11 01:20:53 -07002485 block_group = (ino - 1) / EXT4_INODES_PER_GROUP(sb);
2486 if (block_group >= EXT4_SB(sb)->s_groups_count) {
2487 ext4_error(sb,"ext4_get_inode_block","group >= groups count");
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002488 return 0;
2489 }
2490 smp_rmb();
Mingming Cao617ba132006-10-11 01:20:53 -07002491 group_desc = block_group >> EXT4_DESC_PER_BLOCK_BITS(sb);
2492 desc = block_group & (EXT4_DESC_PER_BLOCK(sb) - 1);
2493 bh = EXT4_SB(sb)->s_group_desc[group_desc];
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002494 if (!bh) {
Mingming Cao617ba132006-10-11 01:20:53 -07002495 ext4_error (sb, "ext4_get_inode_block",
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002496 "Descriptor not loaded");
2497 return 0;
2498 }
2499
Alexandre Ratchov0d1ee422006-10-11 01:21:14 -07002500 gdp = (struct ext4_group_desc *)((__u8 *)bh->b_data +
2501 desc * EXT4_DESC_SIZE(sb));
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002502 /*
2503 * Figure out the offset within the block group inode table
2504 */
Mingming Cao617ba132006-10-11 01:20:53 -07002505 offset = ((ino - 1) % EXT4_INODES_PER_GROUP(sb)) *
2506 EXT4_INODE_SIZE(sb);
Alexandre Ratchov8fadc142006-10-11 01:21:15 -07002507 block = ext4_inode_table(sb, gdp) +
2508 (offset >> EXT4_BLOCK_SIZE_BITS(sb));
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002509
2510 iloc->block_group = block_group;
Mingming Cao617ba132006-10-11 01:20:53 -07002511 iloc->offset = offset & (EXT4_BLOCK_SIZE(sb) - 1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002512 return block;
2513}
2514
2515/*
Mingming Cao617ba132006-10-11 01:20:53 -07002516 * ext4_get_inode_loc returns with an extra refcount against the inode's
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002517 * underlying buffer_head on success. If 'in_mem' is true, we have all
2518 * data in memory that is needed to recreate the on-disk version of this
2519 * inode.
2520 */
Mingming Cao617ba132006-10-11 01:20:53 -07002521static int __ext4_get_inode_loc(struct inode *inode,
2522 struct ext4_iloc *iloc, int in_mem)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002523{
Mingming Cao617ba132006-10-11 01:20:53 -07002524 ext4_fsblk_t block;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002525 struct buffer_head *bh;
2526
Mingming Cao617ba132006-10-11 01:20:53 -07002527 block = ext4_get_inode_block(inode->i_sb, inode->i_ino, iloc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002528 if (!block)
2529 return -EIO;
2530
2531 bh = sb_getblk(inode->i_sb, block);
2532 if (!bh) {
Mingming Cao617ba132006-10-11 01:20:53 -07002533 ext4_error (inode->i_sb, "ext4_get_inode_loc",
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002534 "unable to read inode block - "
Mingming Cao2ae02102006-10-11 01:21:11 -07002535 "inode=%lu, block=%llu",
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002536 inode->i_ino, block);
2537 return -EIO;
2538 }
2539 if (!buffer_uptodate(bh)) {
2540 lock_buffer(bh);
2541 if (buffer_uptodate(bh)) {
2542 /* someone brought it uptodate while we waited */
2543 unlock_buffer(bh);
2544 goto has_buffer;
2545 }
2546
2547 /*
2548 * If we have all information of the inode in memory and this
2549 * is the only valid inode in the block, we need not read the
2550 * block.
2551 */
2552 if (in_mem) {
2553 struct buffer_head *bitmap_bh;
Mingming Cao617ba132006-10-11 01:20:53 -07002554 struct ext4_group_desc *desc;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002555 int inodes_per_buffer;
2556 int inode_offset, i;
2557 int block_group;
2558 int start;
2559
2560 block_group = (inode->i_ino - 1) /
Mingming Cao617ba132006-10-11 01:20:53 -07002561 EXT4_INODES_PER_GROUP(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002562 inodes_per_buffer = bh->b_size /
Mingming Cao617ba132006-10-11 01:20:53 -07002563 EXT4_INODE_SIZE(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002564 inode_offset = ((inode->i_ino - 1) %
Mingming Cao617ba132006-10-11 01:20:53 -07002565 EXT4_INODES_PER_GROUP(inode->i_sb));
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002566 start = inode_offset & ~(inodes_per_buffer - 1);
2567
2568 /* Is the inode bitmap in cache? */
Mingming Cao617ba132006-10-11 01:20:53 -07002569 desc = ext4_get_group_desc(inode->i_sb,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002570 block_group, NULL);
2571 if (!desc)
2572 goto make_io;
2573
2574 bitmap_bh = sb_getblk(inode->i_sb,
Alexandre Ratchov8fadc142006-10-11 01:21:15 -07002575 ext4_inode_bitmap(inode->i_sb, desc));
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002576 if (!bitmap_bh)
2577 goto make_io;
2578
2579 /*
2580 * If the inode bitmap isn't in cache then the
2581 * optimisation may end up performing two reads instead
2582 * of one, so skip it.
2583 */
2584 if (!buffer_uptodate(bitmap_bh)) {
2585 brelse(bitmap_bh);
2586 goto make_io;
2587 }
2588 for (i = start; i < start + inodes_per_buffer; i++) {
2589 if (i == inode_offset)
2590 continue;
Mingming Cao617ba132006-10-11 01:20:53 -07002591 if (ext4_test_bit(i, bitmap_bh->b_data))
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002592 break;
2593 }
2594 brelse(bitmap_bh);
2595 if (i == start + inodes_per_buffer) {
2596 /* all other inodes are free, so skip I/O */
2597 memset(bh->b_data, 0, bh->b_size);
2598 set_buffer_uptodate(bh);
2599 unlock_buffer(bh);
2600 goto has_buffer;
2601 }
2602 }
2603
2604make_io:
2605 /*
2606 * There are other valid inodes in the buffer, this inode
2607 * has in-inode xattrs, or we don't have this inode in memory.
2608 * Read the block from disk.
2609 */
2610 get_bh(bh);
2611 bh->b_end_io = end_buffer_read_sync;
2612 submit_bh(READ_META, bh);
2613 wait_on_buffer(bh);
2614 if (!buffer_uptodate(bh)) {
Mingming Cao617ba132006-10-11 01:20:53 -07002615 ext4_error(inode->i_sb, "ext4_get_inode_loc",
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002616 "unable to read inode block - "
Mingming Cao2ae02102006-10-11 01:21:11 -07002617 "inode=%lu, block=%llu",
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002618 inode->i_ino, block);
2619 brelse(bh);
2620 return -EIO;
2621 }
2622 }
2623has_buffer:
2624 iloc->bh = bh;
2625 return 0;
2626}
2627
Mingming Cao617ba132006-10-11 01:20:53 -07002628int ext4_get_inode_loc(struct inode *inode, struct ext4_iloc *iloc)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002629{
2630 /* We have all inode data except xattrs in memory here. */
Mingming Cao617ba132006-10-11 01:20:53 -07002631 return __ext4_get_inode_loc(inode, iloc,
2632 !(EXT4_I(inode)->i_state & EXT4_STATE_XATTR));
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002633}
2634
Mingming Cao617ba132006-10-11 01:20:53 -07002635void ext4_set_inode_flags(struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002636{
Mingming Cao617ba132006-10-11 01:20:53 -07002637 unsigned int flags = EXT4_I(inode)->i_flags;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002638
2639 inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
Mingming Cao617ba132006-10-11 01:20:53 -07002640 if (flags & EXT4_SYNC_FL)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002641 inode->i_flags |= S_SYNC;
Mingming Cao617ba132006-10-11 01:20:53 -07002642 if (flags & EXT4_APPEND_FL)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002643 inode->i_flags |= S_APPEND;
Mingming Cao617ba132006-10-11 01:20:53 -07002644 if (flags & EXT4_IMMUTABLE_FL)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002645 inode->i_flags |= S_IMMUTABLE;
Mingming Cao617ba132006-10-11 01:20:53 -07002646 if (flags & EXT4_NOATIME_FL)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002647 inode->i_flags |= S_NOATIME;
Mingming Cao617ba132006-10-11 01:20:53 -07002648 if (flags & EXT4_DIRSYNC_FL)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002649 inode->i_flags |= S_DIRSYNC;
2650}
2651
Mingming Cao617ba132006-10-11 01:20:53 -07002652void ext4_read_inode(struct inode * inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002653{
Mingming Cao617ba132006-10-11 01:20:53 -07002654 struct ext4_iloc iloc;
2655 struct ext4_inode *raw_inode;
2656 struct ext4_inode_info *ei = EXT4_I(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002657 struct buffer_head *bh;
2658 int block;
2659
Mingming Cao617ba132006-10-11 01:20:53 -07002660#ifdef CONFIG_EXT4DEV_FS_POSIX_ACL
2661 ei->i_acl = EXT4_ACL_NOT_CACHED;
2662 ei->i_default_acl = EXT4_ACL_NOT_CACHED;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002663#endif
2664 ei->i_block_alloc_info = NULL;
2665
Mingming Cao617ba132006-10-11 01:20:53 -07002666 if (__ext4_get_inode_loc(inode, &iloc, 0))
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002667 goto bad_inode;
2668 bh = iloc.bh;
Mingming Cao617ba132006-10-11 01:20:53 -07002669 raw_inode = ext4_raw_inode(&iloc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002670 inode->i_mode = le16_to_cpu(raw_inode->i_mode);
2671 inode->i_uid = (uid_t)le16_to_cpu(raw_inode->i_uid_low);
2672 inode->i_gid = (gid_t)le16_to_cpu(raw_inode->i_gid_low);
2673 if(!(test_opt (inode->i_sb, NO_UID32))) {
2674 inode->i_uid |= le16_to_cpu(raw_inode->i_uid_high) << 16;
2675 inode->i_gid |= le16_to_cpu(raw_inode->i_gid_high) << 16;
2676 }
2677 inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);
2678 inode->i_size = le32_to_cpu(raw_inode->i_size);
2679 inode->i_atime.tv_sec = le32_to_cpu(raw_inode->i_atime);
2680 inode->i_ctime.tv_sec = le32_to_cpu(raw_inode->i_ctime);
2681 inode->i_mtime.tv_sec = le32_to_cpu(raw_inode->i_mtime);
2682 inode->i_atime.tv_nsec = inode->i_ctime.tv_nsec = inode->i_mtime.tv_nsec = 0;
2683
2684 ei->i_state = 0;
2685 ei->i_dir_start_lookup = 0;
2686 ei->i_dtime = le32_to_cpu(raw_inode->i_dtime);
2687 /* We now have enough fields to check if the inode was active or not.
2688 * This is needed because nfsd might try to access dead inodes
2689 * the test is that same one that e2fsck uses
2690 * NeilBrown 1999oct15
2691 */
2692 if (inode->i_nlink == 0) {
2693 if (inode->i_mode == 0 ||
Mingming Cao617ba132006-10-11 01:20:53 -07002694 !(EXT4_SB(inode->i_sb)->s_mount_state & EXT4_ORPHAN_FS)) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002695 /* this inode is deleted */
2696 brelse (bh);
2697 goto bad_inode;
2698 }
2699 /* The only unlinked inodes we let through here have
2700 * valid i_mode and are being read by the orphan
2701 * recovery code: that's fine, we're about to complete
2702 * the process of deleting those. */
2703 }
2704 inode->i_blocks = le32_to_cpu(raw_inode->i_blocks);
2705 ei->i_flags = le32_to_cpu(raw_inode->i_flags);
Mingming Cao617ba132006-10-11 01:20:53 -07002706#ifdef EXT4_FRAGMENTS
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002707 ei->i_faddr = le32_to_cpu(raw_inode->i_faddr);
2708 ei->i_frag_no = raw_inode->i_frag;
2709 ei->i_frag_size = raw_inode->i_fsize;
2710#endif
2711 ei->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);
Mingming Cao9b8f1f02006-10-11 01:21:13 -07002712 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
2713 cpu_to_le32(EXT4_OS_HURD))
Badari Pulavartya1ddeb72006-10-11 01:21:09 -07002714 ei->i_file_acl |=
2715 ((__u64)le16_to_cpu(raw_inode->i_file_acl_high)) << 32;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002716 if (!S_ISREG(inode->i_mode)) {
2717 ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
2718 } else {
2719 inode->i_size |=
2720 ((__u64)le32_to_cpu(raw_inode->i_size_high)) << 32;
2721 }
2722 ei->i_disksize = inode->i_size;
2723 inode->i_generation = le32_to_cpu(raw_inode->i_generation);
2724 ei->i_block_group = iloc.block_group;
2725 /*
2726 * NOTE! The in-memory inode i_data array is in little-endian order
2727 * even on big-endian machines: we do NOT byteswap the block numbers!
2728 */
Mingming Cao617ba132006-10-11 01:20:53 -07002729 for (block = 0; block < EXT4_N_BLOCKS; block++)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002730 ei->i_data[block] = raw_inode->i_block[block];
2731 INIT_LIST_HEAD(&ei->i_orphan);
2732
Mingming Cao617ba132006-10-11 01:20:53 -07002733 if (inode->i_ino >= EXT4_FIRST_INO(inode->i_sb) + 1 &&
2734 EXT4_INODE_SIZE(inode->i_sb) > EXT4_GOOD_OLD_INODE_SIZE) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002735 /*
2736 * When mke2fs creates big inodes it does not zero out
Mingming Cao617ba132006-10-11 01:20:53 -07002737 * the unused bytes above EXT4_GOOD_OLD_INODE_SIZE,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002738 * so ignore those first few inodes.
2739 */
2740 ei->i_extra_isize = le16_to_cpu(raw_inode->i_extra_isize);
Mingming Cao617ba132006-10-11 01:20:53 -07002741 if (EXT4_GOOD_OLD_INODE_SIZE + ei->i_extra_isize >
2742 EXT4_INODE_SIZE(inode->i_sb))
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002743 goto bad_inode;
2744 if (ei->i_extra_isize == 0) {
2745 /* The extra space is currently unused. Use it. */
Mingming Cao617ba132006-10-11 01:20:53 -07002746 ei->i_extra_isize = sizeof(struct ext4_inode) -
2747 EXT4_GOOD_OLD_INODE_SIZE;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002748 } else {
2749 __le32 *magic = (void *)raw_inode +
Mingming Cao617ba132006-10-11 01:20:53 -07002750 EXT4_GOOD_OLD_INODE_SIZE +
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002751 ei->i_extra_isize;
Mingming Cao617ba132006-10-11 01:20:53 -07002752 if (*magic == cpu_to_le32(EXT4_XATTR_MAGIC))
2753 ei->i_state |= EXT4_STATE_XATTR;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002754 }
2755 } else
2756 ei->i_extra_isize = 0;
2757
2758 if (S_ISREG(inode->i_mode)) {
Mingming Cao617ba132006-10-11 01:20:53 -07002759 inode->i_op = &ext4_file_inode_operations;
2760 inode->i_fop = &ext4_file_operations;
2761 ext4_set_aops(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002762 } else if (S_ISDIR(inode->i_mode)) {
Mingming Cao617ba132006-10-11 01:20:53 -07002763 inode->i_op = &ext4_dir_inode_operations;
2764 inode->i_fop = &ext4_dir_operations;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002765 } else if (S_ISLNK(inode->i_mode)) {
Mingming Cao617ba132006-10-11 01:20:53 -07002766 if (ext4_inode_is_fast_symlink(inode))
2767 inode->i_op = &ext4_fast_symlink_inode_operations;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002768 else {
Mingming Cao617ba132006-10-11 01:20:53 -07002769 inode->i_op = &ext4_symlink_inode_operations;
2770 ext4_set_aops(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002771 }
2772 } else {
Mingming Cao617ba132006-10-11 01:20:53 -07002773 inode->i_op = &ext4_special_inode_operations;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002774 if (raw_inode->i_block[0])
2775 init_special_inode(inode, inode->i_mode,
2776 old_decode_dev(le32_to_cpu(raw_inode->i_block[0])));
2777 else
2778 init_special_inode(inode, inode->i_mode,
2779 new_decode_dev(le32_to_cpu(raw_inode->i_block[1])));
2780 }
2781 brelse (iloc.bh);
Mingming Cao617ba132006-10-11 01:20:53 -07002782 ext4_set_inode_flags(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002783 return;
2784
2785bad_inode:
2786 make_bad_inode(inode);
2787 return;
2788}
2789
2790/*
2791 * Post the struct inode info into an on-disk inode location in the
2792 * buffer-cache. This gobbles the caller's reference to the
2793 * buffer_head in the inode location struct.
2794 *
2795 * The caller must have write access to iloc->bh.
2796 */
Mingming Cao617ba132006-10-11 01:20:53 -07002797static int ext4_do_update_inode(handle_t *handle,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002798 struct inode *inode,
Mingming Cao617ba132006-10-11 01:20:53 -07002799 struct ext4_iloc *iloc)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002800{
Mingming Cao617ba132006-10-11 01:20:53 -07002801 struct ext4_inode *raw_inode = ext4_raw_inode(iloc);
2802 struct ext4_inode_info *ei = EXT4_I(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002803 struct buffer_head *bh = iloc->bh;
2804 int err = 0, rc, block;
2805
2806 /* For fields not not tracking in the in-memory inode,
2807 * initialise them to zero for new inodes. */
Mingming Cao617ba132006-10-11 01:20:53 -07002808 if (ei->i_state & EXT4_STATE_NEW)
2809 memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002810
2811 raw_inode->i_mode = cpu_to_le16(inode->i_mode);
2812 if(!(test_opt(inode->i_sb, NO_UID32))) {
2813 raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
2814 raw_inode->i_gid_low = cpu_to_le16(low_16_bits(inode->i_gid));
2815/*
2816 * Fix up interoperability with old kernels. Otherwise, old inodes get
2817 * re-used with the upper 16 bits of the uid/gid intact
2818 */
2819 if(!ei->i_dtime) {
2820 raw_inode->i_uid_high =
2821 cpu_to_le16(high_16_bits(inode->i_uid));
2822 raw_inode->i_gid_high =
2823 cpu_to_le16(high_16_bits(inode->i_gid));
2824 } else {
2825 raw_inode->i_uid_high = 0;
2826 raw_inode->i_gid_high = 0;
2827 }
2828 } else {
2829 raw_inode->i_uid_low =
2830 cpu_to_le16(fs_high2lowuid(inode->i_uid));
2831 raw_inode->i_gid_low =
2832 cpu_to_le16(fs_high2lowgid(inode->i_gid));
2833 raw_inode->i_uid_high = 0;
2834 raw_inode->i_gid_high = 0;
2835 }
2836 raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);
2837 raw_inode->i_size = cpu_to_le32(ei->i_disksize);
2838 raw_inode->i_atime = cpu_to_le32(inode->i_atime.tv_sec);
2839 raw_inode->i_ctime = cpu_to_le32(inode->i_ctime.tv_sec);
2840 raw_inode->i_mtime = cpu_to_le32(inode->i_mtime.tv_sec);
2841 raw_inode->i_blocks = cpu_to_le32(inode->i_blocks);
2842 raw_inode->i_dtime = cpu_to_le32(ei->i_dtime);
2843 raw_inode->i_flags = cpu_to_le32(ei->i_flags);
Mingming Cao617ba132006-10-11 01:20:53 -07002844#ifdef EXT4_FRAGMENTS
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002845 raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
2846 raw_inode->i_frag = ei->i_frag_no;
2847 raw_inode->i_fsize = ei->i_frag_size;
2848#endif
Mingming Cao9b8f1f02006-10-11 01:21:13 -07002849 if (EXT4_SB(inode->i_sb)->s_es->s_creator_os !=
2850 cpu_to_le32(EXT4_OS_HURD))
Badari Pulavartya1ddeb72006-10-11 01:21:09 -07002851 raw_inode->i_file_acl_high =
2852 cpu_to_le16(ei->i_file_acl >> 32);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002853 raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
2854 if (!S_ISREG(inode->i_mode)) {
2855 raw_inode->i_dir_acl = cpu_to_le32(ei->i_dir_acl);
2856 } else {
2857 raw_inode->i_size_high =
2858 cpu_to_le32(ei->i_disksize >> 32);
2859 if (ei->i_disksize > 0x7fffffffULL) {
2860 struct super_block *sb = inode->i_sb;
Mingming Cao617ba132006-10-11 01:20:53 -07002861 if (!EXT4_HAS_RO_COMPAT_FEATURE(sb,
2862 EXT4_FEATURE_RO_COMPAT_LARGE_FILE) ||
2863 EXT4_SB(sb)->s_es->s_rev_level ==
2864 cpu_to_le32(EXT4_GOOD_OLD_REV)) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002865 /* If this is the first large file
2866 * created, add a flag to the superblock.
2867 */
Mingming Cao617ba132006-10-11 01:20:53 -07002868 err = ext4_journal_get_write_access(handle,
2869 EXT4_SB(sb)->s_sbh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002870 if (err)
2871 goto out_brelse;
Mingming Cao617ba132006-10-11 01:20:53 -07002872 ext4_update_dynamic_rev(sb);
2873 EXT4_SET_RO_COMPAT_FEATURE(sb,
2874 EXT4_FEATURE_RO_COMPAT_LARGE_FILE);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002875 sb->s_dirt = 1;
2876 handle->h_sync = 1;
Mingming Cao617ba132006-10-11 01:20:53 -07002877 err = ext4_journal_dirty_metadata(handle,
2878 EXT4_SB(sb)->s_sbh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002879 }
2880 }
2881 }
2882 raw_inode->i_generation = cpu_to_le32(inode->i_generation);
2883 if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode)) {
2884 if (old_valid_dev(inode->i_rdev)) {
2885 raw_inode->i_block[0] =
2886 cpu_to_le32(old_encode_dev(inode->i_rdev));
2887 raw_inode->i_block[1] = 0;
2888 } else {
2889 raw_inode->i_block[0] = 0;
2890 raw_inode->i_block[1] =
2891 cpu_to_le32(new_encode_dev(inode->i_rdev));
2892 raw_inode->i_block[2] = 0;
2893 }
Mingming Cao617ba132006-10-11 01:20:53 -07002894 } else for (block = 0; block < EXT4_N_BLOCKS; block++)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002895 raw_inode->i_block[block] = ei->i_data[block];
2896
2897 if (ei->i_extra_isize)
2898 raw_inode->i_extra_isize = cpu_to_le16(ei->i_extra_isize);
2899
Mingming Cao617ba132006-10-11 01:20:53 -07002900 BUFFER_TRACE(bh, "call ext4_journal_dirty_metadata");
2901 rc = ext4_journal_dirty_metadata(handle, bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002902 if (!err)
2903 err = rc;
Mingming Cao617ba132006-10-11 01:20:53 -07002904 ei->i_state &= ~EXT4_STATE_NEW;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002905
2906out_brelse:
2907 brelse (bh);
Mingming Cao617ba132006-10-11 01:20:53 -07002908 ext4_std_error(inode->i_sb, err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002909 return err;
2910}
2911
2912/*
Mingming Cao617ba132006-10-11 01:20:53 -07002913 * ext4_write_inode()
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002914 *
2915 * We are called from a few places:
2916 *
2917 * - Within generic_file_write() for O_SYNC files.
2918 * Here, there will be no transaction running. We wait for any running
2919 * trasnaction to commit.
2920 *
2921 * - Within sys_sync(), kupdate and such.
2922 * We wait on commit, if tol to.
2923 *
2924 * - Within prune_icache() (PF_MEMALLOC == true)
2925 * Here we simply return. We can't afford to block kswapd on the
2926 * journal commit.
2927 *
2928 * In all cases it is actually safe for us to return without doing anything,
2929 * because the inode has been copied into a raw inode buffer in
Mingming Cao617ba132006-10-11 01:20:53 -07002930 * ext4_mark_inode_dirty(). This is a correctness thing for O_SYNC and for
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002931 * knfsd.
2932 *
2933 * Note that we are absolutely dependent upon all inode dirtiers doing the
2934 * right thing: they *must* call mark_inode_dirty() after dirtying info in
2935 * which we are interested.
2936 *
2937 * It would be a bug for them to not do this. The code:
2938 *
2939 * mark_inode_dirty(inode)
2940 * stuff();
2941 * inode->i_size = expr;
2942 *
2943 * is in error because a kswapd-driven write_inode() could occur while
2944 * `stuff()' is running, and the new i_size will be lost. Plus the inode
2945 * will no longer be on the superblock's dirty inode list.
2946 */
Mingming Cao617ba132006-10-11 01:20:53 -07002947int ext4_write_inode(struct inode *inode, int wait)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002948{
2949 if (current->flags & PF_MEMALLOC)
2950 return 0;
2951
Mingming Cao617ba132006-10-11 01:20:53 -07002952 if (ext4_journal_current_handle()) {
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002953 jbd_debug(0, "called recursively, non-PF_MEMALLOC!\n");
2954 dump_stack();
2955 return -EIO;
2956 }
2957
2958 if (!wait)
2959 return 0;
2960
Mingming Cao617ba132006-10-11 01:20:53 -07002961 return ext4_force_commit(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002962}
2963
2964/*
Mingming Cao617ba132006-10-11 01:20:53 -07002965 * ext4_setattr()
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002966 *
2967 * Called from notify_change.
2968 *
2969 * We want to trap VFS attempts to truncate the file as soon as
2970 * possible. In particular, we want to make sure that when the VFS
2971 * shrinks i_size, we put the inode on the orphan list and modify
2972 * i_disksize immediately, so that during the subsequent flushing of
2973 * dirty pages and freeing of disk blocks, we can guarantee that any
2974 * commit will leave the blocks being flushed in an unused state on
2975 * disk. (On recovery, the inode will get truncated and the blocks will
2976 * be freed, so we have a strong guarantee that no future commit will
2977 * leave these blocks visible to the user.)
2978 *
2979 * Called with inode->sem down.
2980 */
Mingming Cao617ba132006-10-11 01:20:53 -07002981int ext4_setattr(struct dentry *dentry, struct iattr *attr)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002982{
2983 struct inode *inode = dentry->d_inode;
2984 int error, rc = 0;
2985 const unsigned int ia_valid = attr->ia_valid;
2986
2987 error = inode_change_ok(inode, attr);
2988 if (error)
2989 return error;
2990
2991 if ((ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid) ||
2992 (ia_valid & ATTR_GID && attr->ia_gid != inode->i_gid)) {
2993 handle_t *handle;
2994
2995 /* (user+group)*(old+new) structure, inode write (sb,
2996 * inode block, ? - but truncate inode update has it) */
Mingming Cao617ba132006-10-11 01:20:53 -07002997 handle = ext4_journal_start(inode, 2*(EXT4_QUOTA_INIT_BLOCKS(inode->i_sb)+
2998 EXT4_QUOTA_DEL_BLOCKS(inode->i_sb))+3);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07002999 if (IS_ERR(handle)) {
3000 error = PTR_ERR(handle);
3001 goto err_out;
3002 }
3003 error = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
3004 if (error) {
Mingming Cao617ba132006-10-11 01:20:53 -07003005 ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003006 return error;
3007 }
3008 /* Update corresponding info in inode so that everything is in
3009 * one transaction */
3010 if (attr->ia_valid & ATTR_UID)
3011 inode->i_uid = attr->ia_uid;
3012 if (attr->ia_valid & ATTR_GID)
3013 inode->i_gid = attr->ia_gid;
Mingming Cao617ba132006-10-11 01:20:53 -07003014 error = ext4_mark_inode_dirty(handle, inode);
3015 ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003016 }
3017
3018 if (S_ISREG(inode->i_mode) &&
3019 attr->ia_valid & ATTR_SIZE && attr->ia_size < inode->i_size) {
3020 handle_t *handle;
3021
Mingming Cao617ba132006-10-11 01:20:53 -07003022 handle = ext4_journal_start(inode, 3);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003023 if (IS_ERR(handle)) {
3024 error = PTR_ERR(handle);
3025 goto err_out;
3026 }
3027
Mingming Cao617ba132006-10-11 01:20:53 -07003028 error = ext4_orphan_add(handle, inode);
3029 EXT4_I(inode)->i_disksize = attr->ia_size;
3030 rc = ext4_mark_inode_dirty(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003031 if (!error)
3032 error = rc;
Mingming Cao617ba132006-10-11 01:20:53 -07003033 ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003034 }
3035
3036 rc = inode_setattr(inode, attr);
3037
Mingming Cao617ba132006-10-11 01:20:53 -07003038 /* If inode_setattr's call to ext4_truncate failed to get a
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003039 * transaction handle at all, we need to clean up the in-core
3040 * orphan list manually. */
3041 if (inode->i_nlink)
Mingming Cao617ba132006-10-11 01:20:53 -07003042 ext4_orphan_del(NULL, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003043
3044 if (!rc && (ia_valid & ATTR_MODE))
Mingming Cao617ba132006-10-11 01:20:53 -07003045 rc = ext4_acl_chmod(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003046
3047err_out:
Mingming Cao617ba132006-10-11 01:20:53 -07003048 ext4_std_error(inode->i_sb, error);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003049 if (!error)
3050 error = rc;
3051 return error;
3052}
3053
3054
3055/*
3056 * How many blocks doth make a writepage()?
3057 *
3058 * With N blocks per page, it may be:
3059 * N data blocks
3060 * 2 indirect block
3061 * 2 dindirect
3062 * 1 tindirect
3063 * N+5 bitmap blocks (from the above)
3064 * N+5 group descriptor summary blocks
3065 * 1 inode block
3066 * 1 superblock.
Mingming Cao617ba132006-10-11 01:20:53 -07003067 * 2 * EXT4_SINGLEDATA_TRANS_BLOCKS for the quote files
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003068 *
Mingming Cao617ba132006-10-11 01:20:53 -07003069 * 3 * (N + 5) + 2 + 2 * EXT4_SINGLEDATA_TRANS_BLOCKS
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003070 *
3071 * With ordered or writeback data it's the same, less the N data blocks.
3072 *
3073 * If the inode's direct blocks can hold an integral number of pages then a
3074 * page cannot straddle two indirect blocks, and we can only touch one indirect
3075 * and dindirect block, and the "5" above becomes "3".
3076 *
3077 * This still overestimates under most circumstances. If we were to pass the
3078 * start and end offsets in here as well we could do block_to_path() on each
3079 * block and work out the exact number of indirects which are touched. Pah.
3080 */
3081
Alex Tomasa86c6182006-10-11 01:21:03 -07003082int ext4_writepage_trans_blocks(struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003083{
Mingming Cao617ba132006-10-11 01:20:53 -07003084 int bpp = ext4_journal_blocks_per_page(inode);
3085 int indirects = (EXT4_NDIR_BLOCKS % bpp) ? 5 : 3;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003086 int ret;
3087
Alex Tomasa86c6182006-10-11 01:21:03 -07003088 if (EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)
3089 return ext4_ext_writepage_trans_blocks(inode, bpp);
3090
Mingming Cao617ba132006-10-11 01:20:53 -07003091 if (ext4_should_journal_data(inode))
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003092 ret = 3 * (bpp + indirects) + 2;
3093 else
3094 ret = 2 * (bpp + indirects) + 2;
3095
3096#ifdef CONFIG_QUOTA
3097 /* We know that structure was already allocated during DQUOT_INIT so
3098 * we will be updating only the data blocks + inodes */
Mingming Cao617ba132006-10-11 01:20:53 -07003099 ret += 2*EXT4_QUOTA_TRANS_BLOCKS(inode->i_sb);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003100#endif
3101
3102 return ret;
3103}
3104
3105/*
Mingming Cao617ba132006-10-11 01:20:53 -07003106 * The caller must have previously called ext4_reserve_inode_write().
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003107 * Give this, we know that the caller already has write access to iloc->bh.
3108 */
Mingming Cao617ba132006-10-11 01:20:53 -07003109int ext4_mark_iloc_dirty(handle_t *handle,
3110 struct inode *inode, struct ext4_iloc *iloc)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003111{
3112 int err = 0;
3113
3114 /* the do_update_inode consumes one bh->b_count */
3115 get_bh(iloc->bh);
3116
Mingming Caodab291a2006-10-11 01:21:01 -07003117 /* ext4_do_update_inode() does jbd2_journal_dirty_metadata */
Mingming Cao617ba132006-10-11 01:20:53 -07003118 err = ext4_do_update_inode(handle, inode, iloc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003119 put_bh(iloc->bh);
3120 return err;
3121}
3122
3123/*
3124 * On success, We end up with an outstanding reference count against
3125 * iloc->bh. This _must_ be cleaned up later.
3126 */
3127
3128int
Mingming Cao617ba132006-10-11 01:20:53 -07003129ext4_reserve_inode_write(handle_t *handle, struct inode *inode,
3130 struct ext4_iloc *iloc)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003131{
3132 int err = 0;
3133 if (handle) {
Mingming Cao617ba132006-10-11 01:20:53 -07003134 err = ext4_get_inode_loc(inode, iloc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003135 if (!err) {
3136 BUFFER_TRACE(iloc->bh, "get_write_access");
Mingming Cao617ba132006-10-11 01:20:53 -07003137 err = ext4_journal_get_write_access(handle, iloc->bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003138 if (err) {
3139 brelse(iloc->bh);
3140 iloc->bh = NULL;
3141 }
3142 }
3143 }
Mingming Cao617ba132006-10-11 01:20:53 -07003144 ext4_std_error(inode->i_sb, err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003145 return err;
3146}
3147
3148/*
3149 * What we do here is to mark the in-core inode as clean with respect to inode
3150 * dirtiness (it may still be data-dirty).
3151 * This means that the in-core inode may be reaped by prune_icache
3152 * without having to perform any I/O. This is a very good thing,
3153 * because *any* task may call prune_icache - even ones which
3154 * have a transaction open against a different journal.
3155 *
3156 * Is this cheating? Not really. Sure, we haven't written the
3157 * inode out, but prune_icache isn't a user-visible syncing function.
3158 * Whenever the user wants stuff synced (sys_sync, sys_msync, sys_fsync)
3159 * we start and wait on commits.
3160 *
3161 * Is this efficient/effective? Well, we're being nice to the system
3162 * by cleaning up our inodes proactively so they can be reaped
3163 * without I/O. But we are potentially leaving up to five seconds'
3164 * worth of inodes floating about which prune_icache wants us to
3165 * write out. One way to fix that would be to get prune_icache()
3166 * to do a write_super() to free up some memory. It has the desired
3167 * effect.
3168 */
Mingming Cao617ba132006-10-11 01:20:53 -07003169int ext4_mark_inode_dirty(handle_t *handle, struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003170{
Mingming Cao617ba132006-10-11 01:20:53 -07003171 struct ext4_iloc iloc;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003172 int err;
3173
3174 might_sleep();
Mingming Cao617ba132006-10-11 01:20:53 -07003175 err = ext4_reserve_inode_write(handle, inode, &iloc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003176 if (!err)
Mingming Cao617ba132006-10-11 01:20:53 -07003177 err = ext4_mark_iloc_dirty(handle, inode, &iloc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003178 return err;
3179}
3180
3181/*
Mingming Cao617ba132006-10-11 01:20:53 -07003182 * ext4_dirty_inode() is called from __mark_inode_dirty()
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003183 *
3184 * We're really interested in the case where a file is being extended.
3185 * i_size has been changed by generic_commit_write() and we thus need
3186 * to include the updated inode in the current transaction.
3187 *
3188 * Also, DQUOT_ALLOC_SPACE() will always dirty the inode when blocks
3189 * are allocated to the file.
3190 *
3191 * If the inode is marked synchronous, we don't honour that here - doing
3192 * so would cause a commit on atime updates, which we don't bother doing.
3193 * We handle synchronous inodes at the highest possible level.
3194 */
Mingming Cao617ba132006-10-11 01:20:53 -07003195void ext4_dirty_inode(struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003196{
Mingming Cao617ba132006-10-11 01:20:53 -07003197 handle_t *current_handle = ext4_journal_current_handle();
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003198 handle_t *handle;
3199
Mingming Cao617ba132006-10-11 01:20:53 -07003200 handle = ext4_journal_start(inode, 2);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003201 if (IS_ERR(handle))
3202 goto out;
3203 if (current_handle &&
3204 current_handle->h_transaction != handle->h_transaction) {
3205 /* This task has a transaction open against a different fs */
3206 printk(KERN_EMERG "%s: transactions do not match!\n",
3207 __FUNCTION__);
3208 } else {
3209 jbd_debug(5, "marking dirty. outer handle=%p\n",
3210 current_handle);
Mingming Cao617ba132006-10-11 01:20:53 -07003211 ext4_mark_inode_dirty(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003212 }
Mingming Cao617ba132006-10-11 01:20:53 -07003213 ext4_journal_stop(handle);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003214out:
3215 return;
3216}
3217
3218#if 0
3219/*
3220 * Bind an inode's backing buffer_head into this transaction, to prevent
3221 * it from being flushed to disk early. Unlike
Mingming Cao617ba132006-10-11 01:20:53 -07003222 * ext4_reserve_inode_write, this leaves behind no bh reference and
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003223 * returns no iloc structure, so the caller needs to repeat the iloc
3224 * lookup to mark the inode dirty later.
3225 */
Mingming Cao617ba132006-10-11 01:20:53 -07003226static int ext4_pin_inode(handle_t *handle, struct inode *inode)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003227{
Mingming Cao617ba132006-10-11 01:20:53 -07003228 struct ext4_iloc iloc;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003229
3230 int err = 0;
3231 if (handle) {
Mingming Cao617ba132006-10-11 01:20:53 -07003232 err = ext4_get_inode_loc(inode, &iloc);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003233 if (!err) {
3234 BUFFER_TRACE(iloc.bh, "get_write_access");
Mingming Caodab291a2006-10-11 01:21:01 -07003235 err = jbd2_journal_get_write_access(handle, iloc.bh);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003236 if (!err)
Mingming Cao617ba132006-10-11 01:20:53 -07003237 err = ext4_journal_dirty_metadata(handle,
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003238 iloc.bh);
3239 brelse(iloc.bh);
3240 }
3241 }
Mingming Cao617ba132006-10-11 01:20:53 -07003242 ext4_std_error(inode->i_sb, err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003243 return err;
3244}
3245#endif
3246
Mingming Cao617ba132006-10-11 01:20:53 -07003247int ext4_change_inode_journal_flag(struct inode *inode, int val)
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003248{
3249 journal_t *journal;
3250 handle_t *handle;
3251 int err;
3252
3253 /*
3254 * We have to be very careful here: changing a data block's
3255 * journaling status dynamically is dangerous. If we write a
3256 * data block to the journal, change the status and then delete
3257 * that block, we risk forgetting to revoke the old log record
3258 * from the journal and so a subsequent replay can corrupt data.
3259 * So, first we make sure that the journal is empty and that
3260 * nobody is changing anything.
3261 */
3262
Mingming Cao617ba132006-10-11 01:20:53 -07003263 journal = EXT4_JOURNAL(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003264 if (is_journal_aborted(journal) || IS_RDONLY(inode))
3265 return -EROFS;
3266
Mingming Caodab291a2006-10-11 01:21:01 -07003267 jbd2_journal_lock_updates(journal);
3268 jbd2_journal_flush(journal);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003269
3270 /*
3271 * OK, there are no updates running now, and all cached data is
3272 * synced to disk. We are now in a completely consistent state
3273 * which doesn't have anything in the journal, and we know that
3274 * no filesystem updates are running, so it is safe to modify
3275 * the inode's in-core data-journaling state flag now.
3276 */
3277
3278 if (val)
Mingming Cao617ba132006-10-11 01:20:53 -07003279 EXT4_I(inode)->i_flags |= EXT4_JOURNAL_DATA_FL;
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003280 else
Mingming Cao617ba132006-10-11 01:20:53 -07003281 EXT4_I(inode)->i_flags &= ~EXT4_JOURNAL_DATA_FL;
3282 ext4_set_aops(inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003283
Mingming Caodab291a2006-10-11 01:21:01 -07003284 jbd2_journal_unlock_updates(journal);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003285
3286 /* Finally we can mark the inode as dirty. */
3287
Mingming Cao617ba132006-10-11 01:20:53 -07003288 handle = ext4_journal_start(inode, 1);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003289 if (IS_ERR(handle))
3290 return PTR_ERR(handle);
3291
Mingming Cao617ba132006-10-11 01:20:53 -07003292 err = ext4_mark_inode_dirty(handle, inode);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003293 handle->h_sync = 1;
Mingming Cao617ba132006-10-11 01:20:53 -07003294 ext4_journal_stop(handle);
3295 ext4_std_error(inode->i_sb, err);
Dave Kleikampac27a0e2006-10-11 01:20:50 -07003296
3297 return err;
3298}