| /* |
| * linux/fs/ext2/xattr.c |
| * |
| * Copyright (C) 2001-2003 Andreas Gruenbacher <agruen@suse.de> |
| * |
| * Fix by Harrison Xing <harrison@mountainviewdata.com>. |
| * Extended attributes for symlinks and special files added per |
| * suggestion of Luka Renko <luka.renko@hermes.si>. |
| * xattr consolidation Copyright (c) 2004 James Morris <jmorris@redhat.com>, |
| * Red Hat Inc. |
| * |
| */ |
| |
| /* |
| * Extended attributes are stored on disk blocks allocated outside of |
| * any inode. The i_file_acl field is then made to point to this allocated |
| * block. If all extended attributes of an inode are identical, these |
| * inodes may share the same extended attribute block. Such situations |
| * are automatically detected by keeping a cache of recent attribute block |
| * numbers and hashes over the block's contents in memory. |
| * |
| * |
| * Extended attribute block layout: |
| * |
| * +------------------+ |
| * | header | |
| * | entry 1 | | |
| * | entry 2 | | growing downwards |
| * | entry 3 | v |
| * | four null bytes | |
| * | . . . | |
| * | value 1 | ^ |
| * | value 3 | | growing upwards |
| * | value 2 | | |
| * +------------------+ |
| * |
| * The block header is followed by multiple entry descriptors. These entry |
| * descriptors are variable in size, and alligned to EXT2_XATTR_PAD |
| * byte boundaries. The entry descriptors are sorted by attribute name, |
| * so that two extended attribute blocks can be compared efficiently. |
| * |
| * Attribute values are aligned to the end of the block, stored in |
| * no specific order. They are also padded to EXT2_XATTR_PAD byte |
| * boundaries. No additional gaps are left between them. |
| * |
| * Locking strategy |
| * ---------------- |
| * EXT2_I(inode)->i_file_acl is protected by EXT2_I(inode)->xattr_sem. |
| * EA blocks are only changed if they are exclusive to an inode, so |
| * holding xattr_sem also means that nothing but the EA block's reference |
| * count will change. Multiple writers to an EA block are synchronized |
| * by the bh lock. No more than a single bh lock is held at any time |
| * to avoid deadlocks. |
| */ |
| |
| #include <linux/buffer_head.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/slab.h> |
| #include <linux/mbcache.h> |
| #include <linux/quotaops.h> |
| #include <linux/rwsem.h> |
| #include "ext2.h" |
| #include "xattr.h" |
| #include "acl.h" |
| |
| #define HDR(bh) ((struct ext2_xattr_header *)((bh)->b_data)) |
| #define ENTRY(ptr) ((struct ext2_xattr_entry *)(ptr)) |
| #define FIRST_ENTRY(bh) ENTRY(HDR(bh)+1) |
| #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) |
| |
| #ifdef EXT2_XATTR_DEBUG |
| # define ea_idebug(inode, f...) do { \ |
| printk(KERN_DEBUG "inode %s:%ld: ", \ |
| inode->i_sb->s_id, inode->i_ino); \ |
| printk(f); \ |
| printk("\n"); \ |
| } while (0) |
| # define ea_bdebug(bh, f...) do { \ |
| char b[BDEVNAME_SIZE]; \ |
| printk(KERN_DEBUG "block %s:%lu: ", \ |
| bdevname(bh->b_bdev, b), \ |
| (unsigned long) bh->b_blocknr); \ |
| printk(f); \ |
| printk("\n"); \ |
| } while (0) |
| #else |
| # define ea_idebug(f...) |
| # define ea_bdebug(f...) |
| #endif |
| |
| static int ext2_xattr_set2(struct inode *, struct buffer_head *, |
| struct ext2_xattr_header *); |
| |
| static int ext2_xattr_cache_insert(struct buffer_head *); |
| static struct buffer_head *ext2_xattr_cache_find(struct inode *, |
| struct ext2_xattr_header *); |
| static void ext2_xattr_rehash(struct ext2_xattr_header *, |
| struct ext2_xattr_entry *); |
| |
| static struct mb_cache *ext2_xattr_cache; |
| |
| static struct xattr_handler *ext2_xattr_handler_map[] = { |
| [EXT2_XATTR_INDEX_USER] = &ext2_xattr_user_handler, |
| #ifdef CONFIG_EXT2_FS_POSIX_ACL |
| [EXT2_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext2_xattr_acl_access_handler, |
| [EXT2_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext2_xattr_acl_default_handler, |
| #endif |
| [EXT2_XATTR_INDEX_TRUSTED] = &ext2_xattr_trusted_handler, |
| #ifdef CONFIG_EXT2_FS_SECURITY |
| [EXT2_XATTR_INDEX_SECURITY] = &ext2_xattr_security_handler, |
| #endif |
| }; |
| |
| struct xattr_handler *ext2_xattr_handlers[] = { |
| &ext2_xattr_user_handler, |
| &ext2_xattr_trusted_handler, |
| #ifdef CONFIG_EXT2_FS_POSIX_ACL |
| &ext2_xattr_acl_access_handler, |
| &ext2_xattr_acl_default_handler, |
| #endif |
| #ifdef CONFIG_EXT2_FS_SECURITY |
| &ext2_xattr_security_handler, |
| #endif |
| NULL |
| }; |
| |
| static inline struct xattr_handler * |
| ext2_xattr_handler(int name_index) |
| { |
| struct xattr_handler *handler = NULL; |
| |
| if (name_index > 0 && name_index < ARRAY_SIZE(ext2_xattr_handler_map)) |
| handler = ext2_xattr_handler_map[name_index]; |
| return handler; |
| } |
| |
| /* |
| * ext2_xattr_get() |
| * |
| * Copy an extended attribute into the buffer |
| * provided, or compute the buffer size required. |
| * Buffer is NULL to compute the size of the buffer required. |
| * |
| * Returns a negative error number on failure, or the number of bytes |
| * used / required on success. |
| */ |
| int |
| ext2_xattr_get(struct inode *inode, int name_index, const char *name, |
| void *buffer, size_t buffer_size) |
| { |
| struct buffer_head *bh = NULL; |
| struct ext2_xattr_entry *entry; |
| size_t name_len, size; |
| char *end; |
| int error; |
| |
| ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", |
| name_index, name, buffer, (long)buffer_size); |
| |
| if (name == NULL) |
| return -EINVAL; |
| down_read(&EXT2_I(inode)->xattr_sem); |
| error = -ENODATA; |
| if (!EXT2_I(inode)->i_file_acl) |
| goto cleanup; |
| ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl); |
| bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); |
| error = -EIO; |
| if (!bh) |
| goto cleanup; |
| ea_bdebug(bh, "b_count=%d, refcount=%d", |
| atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); |
| end = bh->b_data + bh->b_size; |
| if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || |
| HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| bad_block: ext2_error(inode->i_sb, "ext2_xattr_get", |
| "inode %ld: bad block %d", inode->i_ino, |
| EXT2_I(inode)->i_file_acl); |
| error = -EIO; |
| goto cleanup; |
| } |
| /* find named attribute */ |
| name_len = strlen(name); |
| |
| error = -ERANGE; |
| if (name_len > 255) |
| goto cleanup; |
| entry = FIRST_ENTRY(bh); |
| while (!IS_LAST_ENTRY(entry)) { |
| struct ext2_xattr_entry *next = |
| EXT2_XATTR_NEXT(entry); |
| if ((char *)next >= end) |
| goto bad_block; |
| if (name_index == entry->e_name_index && |
| name_len == entry->e_name_len && |
| memcmp(name, entry->e_name, name_len) == 0) |
| goto found; |
| entry = next; |
| } |
| /* Check the remaining name entries */ |
| while (!IS_LAST_ENTRY(entry)) { |
| struct ext2_xattr_entry *next = |
| EXT2_XATTR_NEXT(entry); |
| if ((char *)next >= end) |
| goto bad_block; |
| entry = next; |
| } |
| if (ext2_xattr_cache_insert(bh)) |
| ea_idebug(inode, "cache insert failed"); |
| error = -ENODATA; |
| goto cleanup; |
| found: |
| /* check the buffer size */ |
| if (entry->e_value_block != 0) |
| goto bad_block; |
| size = le32_to_cpu(entry->e_value_size); |
| if (size > inode->i_sb->s_blocksize || |
| le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize) |
| goto bad_block; |
| |
| if (ext2_xattr_cache_insert(bh)) |
| ea_idebug(inode, "cache insert failed"); |
| if (buffer) { |
| error = -ERANGE; |
| if (size > buffer_size) |
| goto cleanup; |
| /* return value of attribute */ |
| memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), |
| size); |
| } |
| error = size; |
| |
| cleanup: |
| brelse(bh); |
| up_read(&EXT2_I(inode)->xattr_sem); |
| |
| return error; |
| } |
| |
| /* |
| * ext2_xattr_list() |
| * |
| * Copy a list of attribute names into the buffer |
| * provided, or compute the buffer size required. |
| * Buffer is NULL to compute the size of the buffer required. |
| * |
| * Returns a negative error number on failure, or the number of bytes |
| * used / required on success. |
| */ |
| static int |
| ext2_xattr_list(struct inode *inode, char *buffer, size_t buffer_size) |
| { |
| struct buffer_head *bh = NULL; |
| struct ext2_xattr_entry *entry; |
| char *end; |
| size_t rest = buffer_size; |
| int error; |
| |
| ea_idebug(inode, "buffer=%p, buffer_size=%ld", |
| buffer, (long)buffer_size); |
| |
| down_read(&EXT2_I(inode)->xattr_sem); |
| error = 0; |
| if (!EXT2_I(inode)->i_file_acl) |
| goto cleanup; |
| ea_idebug(inode, "reading block %d", EXT2_I(inode)->i_file_acl); |
| bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); |
| error = -EIO; |
| if (!bh) |
| goto cleanup; |
| ea_bdebug(bh, "b_count=%d, refcount=%d", |
| atomic_read(&(bh->b_count)), le32_to_cpu(HDR(bh)->h_refcount)); |
| end = bh->b_data + bh->b_size; |
| if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || |
| HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| bad_block: ext2_error(inode->i_sb, "ext2_xattr_list", |
| "inode %ld: bad block %d", inode->i_ino, |
| EXT2_I(inode)->i_file_acl); |
| error = -EIO; |
| goto cleanup; |
| } |
| |
| /* check the on-disk data structure */ |
| entry = FIRST_ENTRY(bh); |
| while (!IS_LAST_ENTRY(entry)) { |
| struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(entry); |
| |
| if ((char *)next >= end) |
| goto bad_block; |
| entry = next; |
| } |
| if (ext2_xattr_cache_insert(bh)) |
| ea_idebug(inode, "cache insert failed"); |
| |
| /* list the attribute names */ |
| for (entry = FIRST_ENTRY(bh); !IS_LAST_ENTRY(entry); |
| entry = EXT2_XATTR_NEXT(entry)) { |
| struct xattr_handler *handler = |
| ext2_xattr_handler(entry->e_name_index); |
| |
| if (handler) { |
| size_t size = handler->list(inode, buffer, rest, |
| entry->e_name, |
| entry->e_name_len); |
| if (buffer) { |
| if (size > rest) { |
| error = -ERANGE; |
| goto cleanup; |
| } |
| buffer += size; |
| } |
| rest -= size; |
| } |
| } |
| error = buffer_size - rest; /* total size */ |
| |
| cleanup: |
| brelse(bh); |
| up_read(&EXT2_I(inode)->xattr_sem); |
| |
| return error; |
| } |
| |
| /* |
| * Inode operation listxattr() |
| * |
| * dentry->d_inode->i_mutex: don't care |
| */ |
| ssize_t |
| ext2_listxattr(struct dentry *dentry, char *buffer, size_t size) |
| { |
| return ext2_xattr_list(dentry->d_inode, buffer, size); |
| } |
| |
| /* |
| * If the EXT2_FEATURE_COMPAT_EXT_ATTR feature of this file system is |
| * not set, set it. |
| */ |
| static void ext2_xattr_update_super_block(struct super_block *sb) |
| { |
| if (EXT2_HAS_COMPAT_FEATURE(sb, EXT2_FEATURE_COMPAT_EXT_ATTR)) |
| return; |
| |
| lock_super(sb); |
| EXT2_SB(sb)->s_es->s_feature_compat |= |
| cpu_to_le32(EXT2_FEATURE_COMPAT_EXT_ATTR); |
| sb->s_dirt = 1; |
| mark_buffer_dirty(EXT2_SB(sb)->s_sbh); |
| unlock_super(sb); |
| } |
| |
| /* |
| * ext2_xattr_set() |
| * |
| * Create, replace or remove an extended attribute for this inode. Buffer |
| * is NULL to remove an existing extended attribute, and non-NULL to |
| * either replace an existing extended attribute, or create a new extended |
| * attribute. The flags XATTR_REPLACE and XATTR_CREATE |
| * specify that an extended attribute must exist and must not exist |
| * previous to the call, respectively. |
| * |
| * Returns 0, or a negative error number on failure. |
| */ |
| int |
| ext2_xattr_set(struct inode *inode, int name_index, const char *name, |
| const void *value, size_t value_len, int flags) |
| { |
| struct super_block *sb = inode->i_sb; |
| struct buffer_head *bh = NULL; |
| struct ext2_xattr_header *header = NULL; |
| struct ext2_xattr_entry *here, *last; |
| size_t name_len, free, min_offs = sb->s_blocksize; |
| int not_found = 1, error; |
| char *end; |
| |
| /* |
| * header -- Points either into bh, or to a temporarily |
| * allocated buffer. |
| * here -- The named entry found, or the place for inserting, within |
| * the block pointed to by header. |
| * last -- Points right after the last named entry within the block |
| * pointed to by header. |
| * min_offs -- The offset of the first value (values are aligned |
| * towards the end of the block). |
| * end -- Points right after the block pointed to by header. |
| */ |
| |
| ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", |
| name_index, name, value, (long)value_len); |
| |
| if (IS_RDONLY(inode)) |
| return -EROFS; |
| if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) |
| return -EPERM; |
| if (value == NULL) |
| value_len = 0; |
| if (name == NULL) |
| return -EINVAL; |
| name_len = strlen(name); |
| if (name_len > 255 || value_len > sb->s_blocksize) |
| return -ERANGE; |
| down_write(&EXT2_I(inode)->xattr_sem); |
| if (EXT2_I(inode)->i_file_acl) { |
| /* The inode already has an extended attribute block. */ |
| bh = sb_bread(sb, EXT2_I(inode)->i_file_acl); |
| error = -EIO; |
| if (!bh) |
| goto cleanup; |
| ea_bdebug(bh, "b_count=%d, refcount=%d", |
| atomic_read(&(bh->b_count)), |
| le32_to_cpu(HDR(bh)->h_refcount)); |
| header = HDR(bh); |
| end = bh->b_data + bh->b_size; |
| if (header->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || |
| header->h_blocks != cpu_to_le32(1)) { |
| bad_block: ext2_error(sb, "ext2_xattr_set", |
| "inode %ld: bad block %d", inode->i_ino, |
| EXT2_I(inode)->i_file_acl); |
| error = -EIO; |
| goto cleanup; |
| } |
| /* Find the named attribute. */ |
| here = FIRST_ENTRY(bh); |
| while (!IS_LAST_ENTRY(here)) { |
| struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(here); |
| if ((char *)next >= end) |
| goto bad_block; |
| if (!here->e_value_block && here->e_value_size) { |
| size_t offs = le16_to_cpu(here->e_value_offs); |
| if (offs < min_offs) |
| min_offs = offs; |
| } |
| not_found = name_index - here->e_name_index; |
| if (!not_found) |
| not_found = name_len - here->e_name_len; |
| if (!not_found) |
| not_found = memcmp(name, here->e_name,name_len); |
| if (not_found <= 0) |
| break; |
| here = next; |
| } |
| last = here; |
| /* We still need to compute min_offs and last. */ |
| while (!IS_LAST_ENTRY(last)) { |
| struct ext2_xattr_entry *next = EXT2_XATTR_NEXT(last); |
| if ((char *)next >= end) |
| goto bad_block; |
| if (!last->e_value_block && last->e_value_size) { |
| size_t offs = le16_to_cpu(last->e_value_offs); |
| if (offs < min_offs) |
| min_offs = offs; |
| } |
| last = next; |
| } |
| |
| /* Check whether we have enough space left. */ |
| free = min_offs - ((char*)last - (char*)header) - sizeof(__u32); |
| } else { |
| /* We will use a new extended attribute block. */ |
| free = sb->s_blocksize - |
| sizeof(struct ext2_xattr_header) - sizeof(__u32); |
| here = last = NULL; /* avoid gcc uninitialized warning. */ |
| } |
| |
| if (not_found) { |
| /* Request to remove a nonexistent attribute? */ |
| error = -ENODATA; |
| if (flags & XATTR_REPLACE) |
| goto cleanup; |
| error = 0; |
| if (value == NULL) |
| goto cleanup; |
| } else { |
| /* Request to create an existing attribute? */ |
| error = -EEXIST; |
| if (flags & XATTR_CREATE) |
| goto cleanup; |
| if (!here->e_value_block && here->e_value_size) { |
| size_t size = le32_to_cpu(here->e_value_size); |
| |
| if (le16_to_cpu(here->e_value_offs) + size > |
| sb->s_blocksize || size > sb->s_blocksize) |
| goto bad_block; |
| free += EXT2_XATTR_SIZE(size); |
| } |
| free += EXT2_XATTR_LEN(name_len); |
| } |
| error = -ENOSPC; |
| if (free < EXT2_XATTR_LEN(name_len) + EXT2_XATTR_SIZE(value_len)) |
| goto cleanup; |
| |
| /* Here we know that we can set the new attribute. */ |
| |
| if (header) { |
| struct mb_cache_entry *ce; |
| |
| /* assert(header == HDR(bh)); */ |
| ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, |
| bh->b_blocknr); |
| lock_buffer(bh); |
| if (header->h_refcount == cpu_to_le32(1)) { |
| ea_bdebug(bh, "modifying in-place"); |
| if (ce) |
| mb_cache_entry_free(ce); |
| /* keep the buffer locked while modifying it. */ |
| } else { |
| int offset; |
| |
| if (ce) |
| mb_cache_entry_release(ce); |
| unlock_buffer(bh); |
| ea_bdebug(bh, "cloning"); |
| header = kmalloc(bh->b_size, GFP_KERNEL); |
| error = -ENOMEM; |
| if (header == NULL) |
| goto cleanup; |
| memcpy(header, HDR(bh), bh->b_size); |
| header->h_refcount = cpu_to_le32(1); |
| |
| offset = (char *)here - bh->b_data; |
| here = ENTRY((char *)header + offset); |
| offset = (char *)last - bh->b_data; |
| last = ENTRY((char *)header + offset); |
| } |
| } else { |
| /* Allocate a buffer where we construct the new block. */ |
| header = kmalloc(sb->s_blocksize, GFP_KERNEL); |
| error = -ENOMEM; |
| if (header == NULL) |
| goto cleanup; |
| memset(header, 0, sb->s_blocksize); |
| end = (char *)header + sb->s_blocksize; |
| header->h_magic = cpu_to_le32(EXT2_XATTR_MAGIC); |
| header->h_blocks = header->h_refcount = cpu_to_le32(1); |
| last = here = ENTRY(header+1); |
| } |
| |
| /* Iff we are modifying the block in-place, bh is locked here. */ |
| |
| if (not_found) { |
| /* Insert the new name. */ |
| size_t size = EXT2_XATTR_LEN(name_len); |
| size_t rest = (char *)last - (char *)here; |
| memmove((char *)here + size, here, rest); |
| memset(here, 0, size); |
| here->e_name_index = name_index; |
| here->e_name_len = name_len; |
| memcpy(here->e_name, name, name_len); |
| } else { |
| if (!here->e_value_block && here->e_value_size) { |
| char *first_val = (char *)header + min_offs; |
| size_t offs = le16_to_cpu(here->e_value_offs); |
| char *val = (char *)header + offs; |
| size_t size = EXT2_XATTR_SIZE( |
| le32_to_cpu(here->e_value_size)); |
| |
| if (size == EXT2_XATTR_SIZE(value_len)) { |
| /* The old and the new value have the same |
| size. Just replace. */ |
| here->e_value_size = cpu_to_le32(value_len); |
| memset(val + size - EXT2_XATTR_PAD, 0, |
| EXT2_XATTR_PAD); /* Clear pad bytes. */ |
| memcpy(val, value, value_len); |
| goto skip_replace; |
| } |
| |
| /* Remove the old value. */ |
| memmove(first_val + size, first_val, val - first_val); |
| memset(first_val, 0, size); |
| here->e_value_offs = 0; |
| min_offs += size; |
| |
| /* Adjust all value offsets. */ |
| last = ENTRY(header+1); |
| while (!IS_LAST_ENTRY(last)) { |
| size_t o = le16_to_cpu(last->e_value_offs); |
| if (!last->e_value_block && o < offs) |
| last->e_value_offs = |
| cpu_to_le16(o + size); |
| last = EXT2_XATTR_NEXT(last); |
| } |
| } |
| if (value == NULL) { |
| /* Remove the old name. */ |
| size_t size = EXT2_XATTR_LEN(name_len); |
| last = ENTRY((char *)last - size); |
| memmove(here, (char*)here + size, |
| (char*)last - (char*)here); |
| memset(last, 0, size); |
| } |
| } |
| |
| if (value != NULL) { |
| /* Insert the new value. */ |
| here->e_value_size = cpu_to_le32(value_len); |
| if (value_len) { |
| size_t size = EXT2_XATTR_SIZE(value_len); |
| char *val = (char *)header + min_offs - size; |
| here->e_value_offs = |
| cpu_to_le16((char *)val - (char *)header); |
| memset(val + size - EXT2_XATTR_PAD, 0, |
| EXT2_XATTR_PAD); /* Clear the pad bytes. */ |
| memcpy(val, value, value_len); |
| } |
| } |
| |
| skip_replace: |
| if (IS_LAST_ENTRY(ENTRY(header+1))) { |
| /* This block is now empty. */ |
| if (bh && header == HDR(bh)) |
| unlock_buffer(bh); /* we were modifying in-place. */ |
| error = ext2_xattr_set2(inode, bh, NULL); |
| } else { |
| ext2_xattr_rehash(header, here); |
| if (bh && header == HDR(bh)) |
| unlock_buffer(bh); /* we were modifying in-place. */ |
| error = ext2_xattr_set2(inode, bh, header); |
| } |
| |
| cleanup: |
| brelse(bh); |
| if (!(bh && header == HDR(bh))) |
| kfree(header); |
| up_write(&EXT2_I(inode)->xattr_sem); |
| |
| return error; |
| } |
| |
| /* |
| * Second half of ext2_xattr_set(): Update the file system. |
| */ |
| static int |
| ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, |
| struct ext2_xattr_header *header) |
| { |
| struct super_block *sb = inode->i_sb; |
| struct buffer_head *new_bh = NULL; |
| int error; |
| |
| if (header) { |
| new_bh = ext2_xattr_cache_find(inode, header); |
| if (new_bh) { |
| /* We found an identical block in the cache. */ |
| if (new_bh == old_bh) { |
| ea_bdebug(new_bh, "keeping this block"); |
| } else { |
| /* The old block is released after updating |
| the inode. */ |
| ea_bdebug(new_bh, "reusing block"); |
| |
| error = -EDQUOT; |
| if (DQUOT_ALLOC_BLOCK(inode, 1)) { |
| unlock_buffer(new_bh); |
| goto cleanup; |
| } |
| HDR(new_bh)->h_refcount = cpu_to_le32(1 + |
| le32_to_cpu(HDR(new_bh)->h_refcount)); |
| ea_bdebug(new_bh, "refcount now=%d", |
| le32_to_cpu(HDR(new_bh)->h_refcount)); |
| } |
| unlock_buffer(new_bh); |
| } else if (old_bh && header == HDR(old_bh)) { |
| /* Keep this block. No need to lock the block as we |
| don't need to change the reference count. */ |
| new_bh = old_bh; |
| get_bh(new_bh); |
| ext2_xattr_cache_insert(new_bh); |
| } else { |
| /* We need to allocate a new block */ |
| int goal = le32_to_cpu(EXT2_SB(sb)->s_es-> |
| s_first_data_block) + |
| EXT2_I(inode)->i_block_group * |
| EXT2_BLOCKS_PER_GROUP(sb); |
| int block = ext2_new_block(inode, goal, |
| NULL, NULL, &error); |
| if (error) |
| goto cleanup; |
| ea_idebug(inode, "creating block %d", block); |
| |
| new_bh = sb_getblk(sb, block); |
| if (!new_bh) { |
| ext2_free_blocks(inode, block, 1); |
| error = -EIO; |
| goto cleanup; |
| } |
| lock_buffer(new_bh); |
| memcpy(new_bh->b_data, header, new_bh->b_size); |
| set_buffer_uptodate(new_bh); |
| unlock_buffer(new_bh); |
| ext2_xattr_cache_insert(new_bh); |
| |
| ext2_xattr_update_super_block(sb); |
| } |
| mark_buffer_dirty(new_bh); |
| if (IS_SYNC(inode)) { |
| sync_dirty_buffer(new_bh); |
| error = -EIO; |
| if (buffer_req(new_bh) && !buffer_uptodate(new_bh)) |
| goto cleanup; |
| } |
| } |
| |
| /* Update the inode. */ |
| EXT2_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; |
| inode->i_ctime = CURRENT_TIME_SEC; |
| if (IS_SYNC(inode)) { |
| error = ext2_sync_inode (inode); |
| /* In case sync failed due to ENOSPC the inode was actually |
| * written (only some dirty data were not) so we just proceed |
| * as if nothing happened and cleanup the unused block */ |
| if (error && error != -ENOSPC) { |
| if (new_bh && new_bh != old_bh) |
| DQUOT_FREE_BLOCK(inode, 1); |
| goto cleanup; |
| } |
| } else |
| mark_inode_dirty(inode); |
| |
| error = 0; |
| if (old_bh && old_bh != new_bh) { |
| struct mb_cache_entry *ce; |
| |
| /* |
| * If there was an old block and we are no longer using it, |
| * release the old block. |
| */ |
| ce = mb_cache_entry_get(ext2_xattr_cache, old_bh->b_bdev, |
| old_bh->b_blocknr); |
| lock_buffer(old_bh); |
| if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) { |
| /* Free the old block. */ |
| if (ce) |
| mb_cache_entry_free(ce); |
| ea_bdebug(old_bh, "freeing"); |
| ext2_free_blocks(inode, old_bh->b_blocknr, 1); |
| /* We let our caller release old_bh, so we |
| * need to duplicate the buffer before. */ |
| get_bh(old_bh); |
| bforget(old_bh); |
| } else { |
| /* Decrement the refcount only. */ |
| HDR(old_bh)->h_refcount = cpu_to_le32( |
| le32_to_cpu(HDR(old_bh)->h_refcount) - 1); |
| if (ce) |
| mb_cache_entry_release(ce); |
| DQUOT_FREE_BLOCK(inode, 1); |
| mark_buffer_dirty(old_bh); |
| ea_bdebug(old_bh, "refcount now=%d", |
| le32_to_cpu(HDR(old_bh)->h_refcount)); |
| } |
| unlock_buffer(old_bh); |
| } |
| |
| cleanup: |
| brelse(new_bh); |
| |
| return error; |
| } |
| |
| /* |
| * ext2_xattr_delete_inode() |
| * |
| * Free extended attribute resources associated with this inode. This |
| * is called immediately before an inode is freed. |
| */ |
| void |
| ext2_xattr_delete_inode(struct inode *inode) |
| { |
| struct buffer_head *bh = NULL; |
| struct mb_cache_entry *ce; |
| |
| down_write(&EXT2_I(inode)->xattr_sem); |
| if (!EXT2_I(inode)->i_file_acl) |
| goto cleanup; |
| bh = sb_bread(inode->i_sb, EXT2_I(inode)->i_file_acl); |
| if (!bh) { |
| ext2_error(inode->i_sb, "ext2_xattr_delete_inode", |
| "inode %ld: block %d read error", inode->i_ino, |
| EXT2_I(inode)->i_file_acl); |
| goto cleanup; |
| } |
| ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count))); |
| if (HDR(bh)->h_magic != cpu_to_le32(EXT2_XATTR_MAGIC) || |
| HDR(bh)->h_blocks != cpu_to_le32(1)) { |
| ext2_error(inode->i_sb, "ext2_xattr_delete_inode", |
| "inode %ld: bad block %d", inode->i_ino, |
| EXT2_I(inode)->i_file_acl); |
| goto cleanup; |
| } |
| ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, bh->b_blocknr); |
| lock_buffer(bh); |
| if (HDR(bh)->h_refcount == cpu_to_le32(1)) { |
| if (ce) |
| mb_cache_entry_free(ce); |
| ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1); |
| get_bh(bh); |
| bforget(bh); |
| } else { |
| HDR(bh)->h_refcount = cpu_to_le32( |
| le32_to_cpu(HDR(bh)->h_refcount) - 1); |
| if (ce) |
| mb_cache_entry_release(ce); |
| mark_buffer_dirty(bh); |
| if (IS_SYNC(inode)) |
| sync_dirty_buffer(bh); |
| DQUOT_FREE_BLOCK(inode, 1); |
| } |
| ea_bdebug(bh, "refcount now=%d", le32_to_cpu(HDR(bh)->h_refcount) - 1); |
| unlock_buffer(bh); |
| EXT2_I(inode)->i_file_acl = 0; |
| |
| cleanup: |
| brelse(bh); |
| up_write(&EXT2_I(inode)->xattr_sem); |
| } |
| |
| /* |
| * ext2_xattr_put_super() |
| * |
| * This is called when a file system is unmounted. |
| */ |
| void |
| ext2_xattr_put_super(struct super_block *sb) |
| { |
| mb_cache_shrink(sb->s_bdev); |
| } |
| |
| |
| /* |
| * ext2_xattr_cache_insert() |
| * |
| * Create a new entry in the extended attribute cache, and insert |
| * it unless such an entry is already in the cache. |
| * |
| * Returns 0, or a negative error number on failure. |
| */ |
| static int |
| ext2_xattr_cache_insert(struct buffer_head *bh) |
| { |
| __u32 hash = le32_to_cpu(HDR(bh)->h_hash); |
| struct mb_cache_entry *ce; |
| int error; |
| |
| ce = mb_cache_entry_alloc(ext2_xattr_cache); |
| if (!ce) |
| return -ENOMEM; |
| error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, &hash); |
| if (error) { |
| mb_cache_entry_free(ce); |
| if (error == -EBUSY) { |
| ea_bdebug(bh, "already in cache (%d cache entries)", |
| atomic_read(&ext2_xattr_cache->c_entry_count)); |
| error = 0; |
| } |
| } else { |
| ea_bdebug(bh, "inserting [%x] (%d cache entries)", (int)hash, |
| atomic_read(&ext2_xattr_cache->c_entry_count)); |
| mb_cache_entry_release(ce); |
| } |
| return error; |
| } |
| |
| /* |
| * ext2_xattr_cmp() |
| * |
| * Compare two extended attribute blocks for equality. |
| * |
| * Returns 0 if the blocks are equal, 1 if they differ, and |
| * a negative error number on errors. |
| */ |
| static int |
| ext2_xattr_cmp(struct ext2_xattr_header *header1, |
| struct ext2_xattr_header *header2) |
| { |
| struct ext2_xattr_entry *entry1, *entry2; |
| |
| entry1 = ENTRY(header1+1); |
| entry2 = ENTRY(header2+1); |
| while (!IS_LAST_ENTRY(entry1)) { |
| if (IS_LAST_ENTRY(entry2)) |
| return 1; |
| if (entry1->e_hash != entry2->e_hash || |
| entry1->e_name_index != entry2->e_name_index || |
| entry1->e_name_len != entry2->e_name_len || |
| entry1->e_value_size != entry2->e_value_size || |
| memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) |
| return 1; |
| if (entry1->e_value_block != 0 || entry2->e_value_block != 0) |
| return -EIO; |
| if (memcmp((char *)header1 + le16_to_cpu(entry1->e_value_offs), |
| (char *)header2 + le16_to_cpu(entry2->e_value_offs), |
| le32_to_cpu(entry1->e_value_size))) |
| return 1; |
| |
| entry1 = EXT2_XATTR_NEXT(entry1); |
| entry2 = EXT2_XATTR_NEXT(entry2); |
| } |
| if (!IS_LAST_ENTRY(entry2)) |
| return 1; |
| return 0; |
| } |
| |
| /* |
| * ext2_xattr_cache_find() |
| * |
| * Find an identical extended attribute block. |
| * |
| * Returns a locked buffer head to the block found, or NULL if such |
| * a block was not found or an error occurred. |
| */ |
| static struct buffer_head * |
| ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header) |
| { |
| __u32 hash = le32_to_cpu(header->h_hash); |
| struct mb_cache_entry *ce; |
| |
| if (!header->h_hash) |
| return NULL; /* never share */ |
| ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); |
| again: |
| ce = mb_cache_entry_find_first(ext2_xattr_cache, 0, |
| inode->i_sb->s_bdev, hash); |
| while (ce) { |
| struct buffer_head *bh; |
| |
| if (IS_ERR(ce)) { |
| if (PTR_ERR(ce) == -EAGAIN) |
| goto again; |
| break; |
| } |
| |
| bh = sb_bread(inode->i_sb, ce->e_block); |
| if (!bh) { |
| ext2_error(inode->i_sb, "ext2_xattr_cache_find", |
| "inode %ld: block %ld read error", |
| inode->i_ino, (unsigned long) ce->e_block); |
| } else { |
| lock_buffer(bh); |
| if (le32_to_cpu(HDR(bh)->h_refcount) > |
| EXT2_XATTR_REFCOUNT_MAX) { |
| ea_idebug(inode, "block %ld refcount %d>%d", |
| (unsigned long) ce->e_block, |
| le32_to_cpu(HDR(bh)->h_refcount), |
| EXT2_XATTR_REFCOUNT_MAX); |
| } else if (!ext2_xattr_cmp(header, HDR(bh))) { |
| ea_bdebug(bh, "b_count=%d", |
| atomic_read(&(bh->b_count))); |
| mb_cache_entry_release(ce); |
| return bh; |
| } |
| unlock_buffer(bh); |
| brelse(bh); |
| } |
| ce = mb_cache_entry_find_next(ce, 0, inode->i_sb->s_bdev, hash); |
| } |
| return NULL; |
| } |
| |
| #define NAME_HASH_SHIFT 5 |
| #define VALUE_HASH_SHIFT 16 |
| |
| /* |
| * ext2_xattr_hash_entry() |
| * |
| * Compute the hash of an extended attribute. |
| */ |
| static inline void ext2_xattr_hash_entry(struct ext2_xattr_header *header, |
| struct ext2_xattr_entry *entry) |
| { |
| __u32 hash = 0; |
| char *name = entry->e_name; |
| int n; |
| |
| for (n=0; n < entry->e_name_len; n++) { |
| hash = (hash << NAME_HASH_SHIFT) ^ |
| (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ |
| *name++; |
| } |
| |
| if (entry->e_value_block == 0 && entry->e_value_size != 0) { |
| __le32 *value = (__le32 *)((char *)header + |
| le16_to_cpu(entry->e_value_offs)); |
| for (n = (le32_to_cpu(entry->e_value_size) + |
| EXT2_XATTR_ROUND) >> EXT2_XATTR_PAD_BITS; n; n--) { |
| hash = (hash << VALUE_HASH_SHIFT) ^ |
| (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ |
| le32_to_cpu(*value++); |
| } |
| } |
| entry->e_hash = cpu_to_le32(hash); |
| } |
| |
| #undef NAME_HASH_SHIFT |
| #undef VALUE_HASH_SHIFT |
| |
| #define BLOCK_HASH_SHIFT 16 |
| |
| /* |
| * ext2_xattr_rehash() |
| * |
| * Re-compute the extended attribute hash value after an entry has changed. |
| */ |
| static void ext2_xattr_rehash(struct ext2_xattr_header *header, |
| struct ext2_xattr_entry *entry) |
| { |
| struct ext2_xattr_entry *here; |
| __u32 hash = 0; |
| |
| ext2_xattr_hash_entry(header, entry); |
| here = ENTRY(header+1); |
| while (!IS_LAST_ENTRY(here)) { |
| if (!here->e_hash) { |
| /* Block is not shared if an entry's hash value == 0 */ |
| hash = 0; |
| break; |
| } |
| hash = (hash << BLOCK_HASH_SHIFT) ^ |
| (hash >> (8*sizeof(hash) - BLOCK_HASH_SHIFT)) ^ |
| le32_to_cpu(here->e_hash); |
| here = EXT2_XATTR_NEXT(here); |
| } |
| header->h_hash = cpu_to_le32(hash); |
| } |
| |
| #undef BLOCK_HASH_SHIFT |
| |
| int __init |
| init_ext2_xattr(void) |
| { |
| ext2_xattr_cache = mb_cache_create("ext2_xattr", NULL, |
| sizeof(struct mb_cache_entry) + |
| sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); |
| if (!ext2_xattr_cache) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| void |
| exit_ext2_xattr(void) |
| { |
| mb_cache_destroy(ext2_xattr_cache); |
| } |