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Alex Tomasa86c6182006-10-11 01:21:03 -07001/*
2 * Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
3 * Written by Alex Tomas <alex@clusterfs.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public Licens
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-
17 */
18
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040019#ifndef _EXT4_EXTENTS
20#define _EXT4_EXTENTS
Alex Tomasa86c6182006-10-11 01:21:03 -070021
Christoph Hellwig3dcf5452008-04-29 18:13:32 -040022#include "ext4.h"
Alex Tomasa86c6182006-10-11 01:21:03 -070023
24/*
Robert P. J. Daybbf2f9f2007-02-17 19:20:16 +010025 * With AGGRESSIVE_TEST defined, the capacity of index/leaf blocks
Randy Dunlapd0d856e2006-10-11 01:21:07 -070026 * becomes very small, so index split, in-depth growing and
27 * other hard changes happen much more often.
28 * This is for debug purposes only.
Alex Tomasa86c6182006-10-11 01:21:03 -070029 */
Robert P. J. Daybbf2f9f2007-02-17 19:20:16 +010030#define AGGRESSIVE_TEST_
Alex Tomasa86c6182006-10-11 01:21:03 -070031
32/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -070033 * With EXTENTS_STATS defined, the number of blocks and extents
34 * are collected in the truncate path. They'll be shown at
35 * umount time.
Alex Tomasa86c6182006-10-11 01:21:03 -070036 */
37#define EXTENTS_STATS__
38
39/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -070040 * If CHECK_BINSEARCH is defined, then the results of the binary search
41 * will also be checked by linear search.
Alex Tomasa86c6182006-10-11 01:21:03 -070042 */
43#define CHECK_BINSEARCH__
44
45/*
Mingming553f9002009-09-18 13:34:55 -040046 * Turn on EXT_DEBUG to get lots of info about extents operations.
Alex Tomasa86c6182006-10-11 01:21:03 -070047 */
48#define EXT_DEBUG__
49#ifdef EXT_DEBUG
50#define ext_debug(a...) printk(a)
51#else
52#define ext_debug(a...)
53#endif
54
55/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -070056 * If EXT_STATS is defined then stats numbers are collected.
57 * These number will be displayed at umount time.
Alex Tomasa86c6182006-10-11 01:21:03 -070058 */
59#define EXT_STATS_
60
61
62/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -070063 * ext4_inode has i_block array (60 bytes total).
64 * The first 12 bytes store ext4_extent_header;
65 * the remainder stores an array of ext4_extent.
Alex Tomasa86c6182006-10-11 01:21:03 -070066 */
67
68/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -070069 * This is the extent on-disk structure.
70 * It's used at the bottom of the tree.
Alex Tomasa86c6182006-10-11 01:21:03 -070071 */
72struct ext4_extent {
73 __le32 ee_block; /* first logical block extent covers */
74 __le16 ee_len; /* number of blocks covered by extent */
75 __le16 ee_start_hi; /* high 16 bits of physical block */
Aneesh Kumar K.Vb3776112007-10-16 18:38:25 -040076 __le32 ee_start_lo; /* low 32 bits of physical block */
Alex Tomasa86c6182006-10-11 01:21:03 -070077};
78
79/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -070080 * This is index on-disk structure.
81 * It's used at all the levels except the bottom.
Alex Tomasa86c6182006-10-11 01:21:03 -070082 */
83struct ext4_extent_idx {
84 __le32 ei_block; /* index covers logical blocks from 'block' */
Aneesh Kumar K.Vd8dd0b42007-10-16 18:38:25 -040085 __le32 ei_leaf_lo; /* pointer to the physical block of the next *
Randy Dunlapd0d856e2006-10-11 01:21:07 -070086 * level. leaf or next index could be there */
Alex Tomasa86c6182006-10-11 01:21:03 -070087 __le16 ei_leaf_hi; /* high 16 bits of physical block */
88 __u16 ei_unused;
89};
90
91/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -070092 * Each block (leaves and indexes), even inode-stored has header.
Alex Tomasa86c6182006-10-11 01:21:03 -070093 */
94struct ext4_extent_header {
95 __le16 eh_magic; /* probably will support different formats */
96 __le16 eh_entries; /* number of valid entries */
97 __le16 eh_max; /* capacity of store in entries */
Randy Dunlapd0d856e2006-10-11 01:21:07 -070098 __le16 eh_depth; /* has tree real underlying blocks? */
Alex Tomasa86c6182006-10-11 01:21:03 -070099 __le32 eh_generation; /* generation of the tree */
100};
101
102#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
103
104/*
Randy Dunlapd0d856e2006-10-11 01:21:07 -0700105 * Array of ext4_ext_path contains path to some extent.
106 * Creation/lookup routines use it for traversal/splitting/etc.
107 * Truncate uses it to simulate recursive walking.
Alex Tomasa86c6182006-10-11 01:21:03 -0700108 */
109struct ext4_ext_path {
Alex Tomasf65e6fb2006-10-11 01:21:05 -0700110 ext4_fsblk_t p_block;
Alex Tomasa86c6182006-10-11 01:21:03 -0700111 __u16 p_depth;
112 struct ext4_extent *p_ext;
113 struct ext4_extent_idx *p_idx;
114 struct ext4_extent_header *p_hdr;
115 struct buffer_head *p_bh;
116};
117
118/*
119 * structure for external API
120 */
121
122#define EXT4_EXT_CACHE_NO 0
123#define EXT4_EXT_CACHE_GAP 1
124#define EXT4_EXT_CACHE_EXTENT 2
125
Eric Sandeen6873fa02008-10-07 00:46:36 -0400126/*
127 * to be called by ext4_ext_walk_space()
128 * negative retcode - error
129 * positive retcode - signal for ext4_ext_walk_space(), see below
130 * callback must return valid extent (passed or newly created)
131 */
132typedef int (*ext_prepare_callback)(struct inode *, struct ext4_ext_path *,
133 struct ext4_ext_cache *,
134 struct ext4_extent *, void *);
135
136#define EXT_CONTINUE 0
137#define EXT_BREAK 1
138#define EXT_REPEAT 2
Alex Tomasa86c6182006-10-11 01:21:03 -0700139
Eric Sandeen0a80e982009-09-17 11:55:58 -0400140/* Maximum logical block in a file; ext4_extent's ee_block is __le32 */
Alex Tomasa86c6182006-10-11 01:21:03 -0700141#define EXT_MAX_BLOCK 0xffffffff
142
Amit Arora749269f2007-07-18 09:02:56 -0400143/*
144 * EXT_INIT_MAX_LEN is the maximum number of blocks we can have in an
145 * initialized extent. This is 2^15 and not (2^16 - 1), since we use the
146 * MSB of ee_len field in the extent datastructure to signify if this
147 * particular extent is an initialized extent or an uninitialized (i.e.
148 * preallocated).
149 * EXT_UNINIT_MAX_LEN is the maximum number of blocks we can have in an
150 * uninitialized extent.
151 * If ee_len is <= 0x8000, it is an initialized extent. Otherwise, it is an
152 * uninitialized one. In other words, if MSB of ee_len is set, it is an
153 * uninitialized extent with only one special scenario when ee_len = 0x8000.
154 * In this case we can not have an uninitialized extent of zero length and
155 * thus we make it as a special case of initialized extent with 0x8000 length.
156 * This way we get better extent-to-group alignment for initialized extents.
157 * Hence, the maximum number of blocks we can have in an *initialized*
158 * extent is 2^15 (32768) and in an *uninitialized* extent is 2^15-1 (32767).
159 */
160#define EXT_INIT_MAX_LEN (1UL << 15)
161#define EXT_UNINIT_MAX_LEN (EXT_INIT_MAX_LEN - 1)
Suparna Bhattacharya471d4012006-10-11 01:21:06 -0700162
Alex Tomasa86c6182006-10-11 01:21:03 -0700163
164#define EXT_FIRST_EXTENT(__hdr__) \
165 ((struct ext4_extent *) (((char *) (__hdr__)) + \
166 sizeof(struct ext4_extent_header)))
167#define EXT_FIRST_INDEX(__hdr__) \
168 ((struct ext4_extent_idx *) (((char *) (__hdr__)) + \
169 sizeof(struct ext4_extent_header)))
170#define EXT_HAS_FREE_INDEX(__path__) \
Dave Kleikamp8c55e202007-05-24 13:04:54 -0400171 (le16_to_cpu((__path__)->p_hdr->eh_entries) \
172 < le16_to_cpu((__path__)->p_hdr->eh_max))
Alex Tomasa86c6182006-10-11 01:21:03 -0700173#define EXT_LAST_EXTENT(__hdr__) \
174 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
175#define EXT_LAST_INDEX(__hdr__) \
176 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_entries) - 1)
177#define EXT_MAX_EXTENT(__hdr__) \
178 (EXT_FIRST_EXTENT((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
179#define EXT_MAX_INDEX(__hdr__) \
180 (EXT_FIRST_INDEX((__hdr__)) + le16_to_cpu((__hdr__)->eh_max) - 1)
181
182static inline struct ext4_extent_header *ext_inode_hdr(struct inode *inode)
183{
184 return (struct ext4_extent_header *) EXT4_I(inode)->i_data;
185}
186
187static inline struct ext4_extent_header *ext_block_hdr(struct buffer_head *bh)
188{
189 return (struct ext4_extent_header *) bh->b_data;
190}
191
192static inline unsigned short ext_depth(struct inode *inode)
193{
194 return le16_to_cpu(ext_inode_hdr(inode)->eh_depth);
195}
196
Alex Tomasa86c6182006-10-11 01:21:03 -0700197static inline void
198ext4_ext_invalidate_cache(struct inode *inode)
199{
200 EXT4_I(inode)->i_cached_extent.ec_type = EXT4_EXT_CACHE_NO;
201}
202
Amit Aroraa2df2a62007-07-17 21:42:41 -0400203static inline void ext4_ext_mark_uninitialized(struct ext4_extent *ext)
204{
Amit Arora749269f2007-07-18 09:02:56 -0400205 /* We can not have an uninitialized extent of zero length! */
206 BUG_ON((le16_to_cpu(ext->ee_len) & ~EXT_INIT_MAX_LEN) == 0);
207 ext->ee_len |= cpu_to_le16(EXT_INIT_MAX_LEN);
Amit Aroraa2df2a62007-07-17 21:42:41 -0400208}
209
210static inline int ext4_ext_is_uninitialized(struct ext4_extent *ext)
211{
Amit Arora749269f2007-07-18 09:02:56 -0400212 /* Extent with ee_len of 0x8000 is treated as an initialized extent */
213 return (le16_to_cpu(ext->ee_len) > EXT_INIT_MAX_LEN);
Amit Aroraa2df2a62007-07-17 21:42:41 -0400214}
215
216static inline int ext4_ext_get_actual_len(struct ext4_extent *ext)
217{
Amit Arora749269f2007-07-18 09:02:56 -0400218 return (le16_to_cpu(ext->ee_len) <= EXT_INIT_MAX_LEN ?
219 le16_to_cpu(ext->ee_len) :
220 (le16_to_cpu(ext->ee_len) - EXT_INIT_MAX_LEN));
Amit Aroraa2df2a62007-07-17 21:42:41 -0400221}
222
Mingming Cao00314622009-09-28 15:49:08 -0400223static inline void ext4_ext_mark_initialized(struct ext4_extent *ext)
224{
225 ext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(ext));
226}
227
Theodore Ts'o9d0be502010-01-01 02:41:30 -0500228extern int ext4_ext_calc_metadata_amount(struct inode *inode,
229 sector_t lblocks);
Akira Fujita748de672009-06-17 19:24:03 -0400230extern ext4_fsblk_t ext_pblock(struct ext4_extent *ex);
Aneesh Kumar K.Vc14c6fd2008-01-28 23:58:26 -0500231extern ext4_fsblk_t idx_pblock(struct ext4_extent_idx *);
232extern void ext4_ext_store_pblock(struct ext4_extent *, ext4_fsblk_t);
Alex Tomasa86c6182006-10-11 01:21:03 -0700233extern int ext4_extent_tree_init(handle_t *, struct inode *);
Mingming Caoee12b632008-08-19 22:16:05 -0400234extern int ext4_ext_calc_credits_for_single_extent(struct inode *inode,
235 int num,
236 struct ext4_ext_path *path);
Akira Fujita748de672009-06-17 19:24:03 -0400237extern int ext4_can_extents_be_merged(struct inode *inode,
238 struct ext4_extent *ex1,
239 struct ext4_extent *ex2);
Amit Arora56055d32007-07-17 21:42:38 -0400240extern int ext4_ext_try_to_merge(struct inode *inode,
241 struct ext4_ext_path *path,
242 struct ext4_extent *);
Amit Arora25d14f92007-05-24 13:04:13 -0400243extern unsigned int ext4_ext_check_overlap(struct inode *, struct ext4_extent *, struct ext4_ext_path *);
Mingming Cao00314622009-09-28 15:49:08 -0400244extern int ext4_ext_insert_extent(handle_t *, struct inode *, struct ext4_ext_path *, struct ext4_extent *, int);
Eric Sandeen6873fa02008-10-07 00:46:36 -0400245extern int ext4_ext_walk_space(struct inode *, ext4_lblk_t, ext4_lblk_t,
246 ext_prepare_callback, void *);
Aneesh Kumar K.V725d26d2008-01-28 23:58:27 -0500247extern struct ext4_ext_path *ext4_ext_find_extent(struct inode *, ext4_lblk_t,
248 struct ext4_ext_path *);
Alex Tomas1988b512008-01-28 23:58:27 -0500249extern int ext4_ext_search_left(struct inode *, struct ext4_ext_path *,
250 ext4_lblk_t *, ext4_fsblk_t *);
251extern int ext4_ext_search_right(struct inode *, struct ext4_ext_path *,
252 ext4_lblk_t *, ext4_fsblk_t *);
Aneesh Kumar K.Vb35905c2008-02-25 16:54:37 -0500253extern void ext4_ext_drop_refs(struct ext4_ext_path *);
Aneesh Kumar K.V7a262f72009-03-27 16:39:58 -0400254extern int ext4_ext_check_inode(struct inode *inode);
Christoph Hellwig3dcf5452008-04-29 18:13:32 -0400255#endif /* _EXT4_EXTENTS */
Alex Tomasa86c6182006-10-11 01:21:03 -0700256