| /* |
| * linux/fs/ext4/xattr.c |
| * |
| * Copyright (C) 2001-2003 Andreas Gruenbacher, <agruen@suse.de> |
| * |
| * Fix by Harrison Xing <harrison@mountainviewdata.com>. |
| * Ext4 code with a lot of help from Eric Jarman <ejarman@acm.org>. |
| * 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. |
| * ea-in-inode support by Alex Tomas <alex@clusterfs.com> aka bzzz |
| * and Andreas Gruenbacher <agruen@suse.de>. |
| */ |
| |
| /* |
| * Extended attributes are stored directly in inodes (on file systems with |
| * inodes bigger than 128 bytes) and on additional disk blocks. The i_file_acl |
| * field contains the block number if an inode uses an additional block. All |
| * attributes must fit in the inode and one additional block. Blocks that |
| * contain the identical set of attributes may be shared among several inodes. |
| * Identical blocks are detected by keeping a cache of blocks that have |
| * recently been accessed. |
| * |
| * The attributes in inodes and on blocks have a different header; the entries |
| * are stored in the same format: |
| * |
| * +------------------+ |
| * | header | |
| * | entry 1 | | |
| * | entry 2 | | growing downwards |
| * | entry 3 | v |
| * | four null bytes | |
| * | . . . | |
| * | value 1 | ^ |
| * | value 3 | | growing upwards |
| * | value 2 | | |
| * +------------------+ |
| * |
| * The header is followed by multiple entry descriptors. In disk blocks, the |
| * entry descriptors are kept sorted. In inodes, they are unsorted. The |
| * attribute values are aligned to the end of the block in no specific order. |
| * |
| * Locking strategy |
| * ---------------- |
| * EXT4_I(inode)->i_file_acl is protected by EXT4_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 can change. Multiple writers to the same block are synchronized |
| * by the buffer lock. |
| */ |
| |
| #include <linux/init.h> |
| #include <linux/fs.h> |
| #include <linux/slab.h> |
| #include <linux/mbcache.h> |
| #include <linux/quotaops.h> |
| #include <linux/rwsem.h> |
| #include "ext4_jbd2.h" |
| #include "ext4.h" |
| #include "xattr.h" |
| #include "acl.h" |
| |
| #define BHDR(bh) ((struct ext4_xattr_header *)((bh)->b_data)) |
| #define ENTRY(ptr) ((struct ext4_xattr_entry *)(ptr)) |
| #define BFIRST(bh) ENTRY(BHDR(bh)+1) |
| #define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0) |
| |
| #ifdef EXT4_XATTR_DEBUG |
| # define ea_idebug(inode, f...) do { \ |
| printk(KERN_DEBUG "inode %s:%lu: ", \ |
| 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 void ext4_xattr_cache_insert(struct buffer_head *); |
| static struct buffer_head *ext4_xattr_cache_find(struct inode *, |
| struct ext4_xattr_header *, |
| struct mb_cache_entry **); |
| static void ext4_xattr_rehash(struct ext4_xattr_header *, |
| struct ext4_xattr_entry *); |
| static int ext4_xattr_list(struct dentry *dentry, char *buffer, |
| size_t buffer_size); |
| |
| static struct mb_cache *ext4_xattr_cache; |
| |
| static struct xattr_handler *ext4_xattr_handler_map[] = { |
| [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, |
| #ifdef CONFIG_EXT4_FS_POSIX_ACL |
| [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &ext4_xattr_acl_access_handler, |
| [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &ext4_xattr_acl_default_handler, |
| #endif |
| [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, |
| #ifdef CONFIG_EXT4_FS_SECURITY |
| [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, |
| #endif |
| }; |
| |
| struct xattr_handler *ext4_xattr_handlers[] = { |
| &ext4_xattr_user_handler, |
| &ext4_xattr_trusted_handler, |
| #ifdef CONFIG_EXT4_FS_POSIX_ACL |
| &ext4_xattr_acl_access_handler, |
| &ext4_xattr_acl_default_handler, |
| #endif |
| #ifdef CONFIG_EXT4_FS_SECURITY |
| &ext4_xattr_security_handler, |
| #endif |
| NULL |
| }; |
| |
| static inline struct xattr_handler * |
| ext4_xattr_handler(int name_index) |
| { |
| struct xattr_handler *handler = NULL; |
| |
| if (name_index > 0 && name_index < ARRAY_SIZE(ext4_xattr_handler_map)) |
| handler = ext4_xattr_handler_map[name_index]; |
| return handler; |
| } |
| |
| /* |
| * Inode operation listxattr() |
| * |
| * dentry->d_inode->i_mutex: don't care |
| */ |
| ssize_t |
| ext4_listxattr(struct dentry *dentry, char *buffer, size_t size) |
| { |
| return ext4_xattr_list(dentry, buffer, size); |
| } |
| |
| static int |
| ext4_xattr_check_names(struct ext4_xattr_entry *entry, void *end) |
| { |
| while (!IS_LAST_ENTRY(entry)) { |
| struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(entry); |
| if ((void *)next >= end) |
| return -EIO; |
| entry = next; |
| } |
| return 0; |
| } |
| |
| static inline int |
| ext4_xattr_check_block(struct buffer_head *bh) |
| { |
| int error; |
| |
| if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || |
| BHDR(bh)->h_blocks != cpu_to_le32(1)) |
| return -EIO; |
| error = ext4_xattr_check_names(BFIRST(bh), bh->b_data + bh->b_size); |
| return error; |
| } |
| |
| static inline int |
| ext4_xattr_check_entry(struct ext4_xattr_entry *entry, size_t size) |
| { |
| size_t value_size = le32_to_cpu(entry->e_value_size); |
| |
| if (entry->e_value_block != 0 || value_size > size || |
| le16_to_cpu(entry->e_value_offs) + value_size > size) |
| return -EIO; |
| return 0; |
| } |
| |
| static int |
| ext4_xattr_find_entry(struct ext4_xattr_entry **pentry, int name_index, |
| const char *name, size_t size, int sorted) |
| { |
| struct ext4_xattr_entry *entry; |
| size_t name_len; |
| int cmp = 1; |
| |
| if (name == NULL) |
| return -EINVAL; |
| name_len = strlen(name); |
| entry = *pentry; |
| for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { |
| cmp = name_index - entry->e_name_index; |
| if (!cmp) |
| cmp = name_len - entry->e_name_len; |
| if (!cmp) |
| cmp = memcmp(name, entry->e_name, name_len); |
| if (cmp <= 0 && (sorted || cmp == 0)) |
| break; |
| } |
| *pentry = entry; |
| if (!cmp && ext4_xattr_check_entry(entry, size)) |
| return -EIO; |
| return cmp ? -ENODATA : 0; |
| } |
| |
| static int |
| ext4_xattr_block_get(struct inode *inode, int name_index, const char *name, |
| void *buffer, size_t buffer_size) |
| { |
| struct buffer_head *bh = NULL; |
| struct ext4_xattr_entry *entry; |
| size_t size; |
| int error; |
| |
| ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", |
| name_index, name, buffer, (long)buffer_size); |
| |
| error = -ENODATA; |
| if (!EXT4_I(inode)->i_file_acl) |
| goto cleanup; |
| ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); |
| bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); |
| if (!bh) |
| goto cleanup; |
| ea_bdebug(bh, "b_count=%d, refcount=%d", |
| atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); |
| if (ext4_xattr_check_block(bh)) { |
| bad_block: |
| ext4_error(inode->i_sb, |
| "inode %lu: bad block %llu", inode->i_ino, |
| EXT4_I(inode)->i_file_acl); |
| error = -EIO; |
| goto cleanup; |
| } |
| ext4_xattr_cache_insert(bh); |
| entry = BFIRST(bh); |
| error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1); |
| if (error == -EIO) |
| goto bad_block; |
| if (error) |
| goto cleanup; |
| size = le32_to_cpu(entry->e_value_size); |
| if (buffer) { |
| error = -ERANGE; |
| if (size > buffer_size) |
| goto cleanup; |
| memcpy(buffer, bh->b_data + le16_to_cpu(entry->e_value_offs), |
| size); |
| } |
| error = size; |
| |
| cleanup: |
| brelse(bh); |
| return error; |
| } |
| |
| static int |
| ext4_xattr_ibody_get(struct inode *inode, int name_index, const char *name, |
| void *buffer, size_t buffer_size) |
| { |
| struct ext4_xattr_ibody_header *header; |
| struct ext4_xattr_entry *entry; |
| struct ext4_inode *raw_inode; |
| struct ext4_iloc iloc; |
| size_t size; |
| void *end; |
| int error; |
| |
| if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) |
| return -ENODATA; |
| error = ext4_get_inode_loc(inode, &iloc); |
| if (error) |
| return error; |
| raw_inode = ext4_raw_inode(&iloc); |
| header = IHDR(inode, raw_inode); |
| entry = IFIRST(header); |
| end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; |
| error = ext4_xattr_check_names(entry, end); |
| if (error) |
| goto cleanup; |
| error = ext4_xattr_find_entry(&entry, name_index, name, |
| end - (void *)entry, 0); |
| if (error) |
| goto cleanup; |
| size = le32_to_cpu(entry->e_value_size); |
| if (buffer) { |
| error = -ERANGE; |
| if (size > buffer_size) |
| goto cleanup; |
| memcpy(buffer, (void *)IFIRST(header) + |
| le16_to_cpu(entry->e_value_offs), size); |
| } |
| error = size; |
| |
| cleanup: |
| brelse(iloc.bh); |
| return error; |
| } |
| |
| /* |
| * ext4_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 |
| ext4_xattr_get(struct inode *inode, int name_index, const char *name, |
| void *buffer, size_t buffer_size) |
| { |
| int error; |
| |
| down_read(&EXT4_I(inode)->xattr_sem); |
| error = ext4_xattr_ibody_get(inode, name_index, name, buffer, |
| buffer_size); |
| if (error == -ENODATA) |
| error = ext4_xattr_block_get(inode, name_index, name, buffer, |
| buffer_size); |
| up_read(&EXT4_I(inode)->xattr_sem); |
| return error; |
| } |
| |
| static int |
| ext4_xattr_list_entries(struct dentry *dentry, struct ext4_xattr_entry *entry, |
| char *buffer, size_t buffer_size) |
| { |
| size_t rest = buffer_size; |
| |
| for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) { |
| struct xattr_handler *handler = |
| ext4_xattr_handler(entry->e_name_index); |
| |
| if (handler) { |
| size_t size = handler->list(dentry, buffer, rest, |
| entry->e_name, |
| entry->e_name_len, |
| handler->flags); |
| if (buffer) { |
| if (size > rest) |
| return -ERANGE; |
| buffer += size; |
| } |
| rest -= size; |
| } |
| } |
| return buffer_size - rest; |
| } |
| |
| static int |
| ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) |
| { |
| struct inode *inode = dentry->d_inode; |
| struct buffer_head *bh = NULL; |
| int error; |
| |
| ea_idebug(inode, "buffer=%p, buffer_size=%ld", |
| buffer, (long)buffer_size); |
| |
| error = 0; |
| if (!EXT4_I(inode)->i_file_acl) |
| goto cleanup; |
| ea_idebug(inode, "reading block %u", EXT4_I(inode)->i_file_acl); |
| bh = sb_bread(inode->i_sb, EXT4_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(BHDR(bh)->h_refcount)); |
| if (ext4_xattr_check_block(bh)) { |
| ext4_error(inode->i_sb, |
| "inode %lu: bad block %llu", inode->i_ino, |
| EXT4_I(inode)->i_file_acl); |
| error = -EIO; |
| goto cleanup; |
| } |
| ext4_xattr_cache_insert(bh); |
| error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size); |
| |
| cleanup: |
| brelse(bh); |
| |
| return error; |
| } |
| |
| static int |
| ext4_xattr_ibody_list(struct dentry *dentry, char *buffer, size_t buffer_size) |
| { |
| struct inode *inode = dentry->d_inode; |
| struct ext4_xattr_ibody_header *header; |
| struct ext4_inode *raw_inode; |
| struct ext4_iloc iloc; |
| void *end; |
| int error; |
| |
| if (!ext4_test_inode_state(inode, EXT4_STATE_XATTR)) |
| return 0; |
| error = ext4_get_inode_loc(inode, &iloc); |
| if (error) |
| return error; |
| raw_inode = ext4_raw_inode(&iloc); |
| header = IHDR(inode, raw_inode); |
| end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; |
| error = ext4_xattr_check_names(IFIRST(header), end); |
| if (error) |
| goto cleanup; |
| error = ext4_xattr_list_entries(dentry, IFIRST(header), |
| buffer, buffer_size); |
| |
| cleanup: |
| brelse(iloc.bh); |
| return error; |
| } |
| |
| /* |
| * ext4_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 |
| ext4_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) |
| { |
| int i_error, b_error; |
| |
| down_read(&EXT4_I(dentry->d_inode)->xattr_sem); |
| i_error = ext4_xattr_ibody_list(dentry, buffer, buffer_size); |
| if (i_error < 0) { |
| b_error = 0; |
| } else { |
| if (buffer) { |
| buffer += i_error; |
| buffer_size -= i_error; |
| } |
| b_error = ext4_xattr_block_list(dentry, buffer, buffer_size); |
| if (b_error < 0) |
| i_error = 0; |
| } |
| up_read(&EXT4_I(dentry->d_inode)->xattr_sem); |
| return i_error + b_error; |
| } |
| |
| /* |
| * If the EXT4_FEATURE_COMPAT_EXT_ATTR feature of this file system is |
| * not set, set it. |
| */ |
| static void ext4_xattr_update_super_block(handle_t *handle, |
| struct super_block *sb) |
| { |
| if (EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR)) |
| return; |
| |
| if (ext4_journal_get_write_access(handle, EXT4_SB(sb)->s_sbh) == 0) { |
| EXT4_SET_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_EXT_ATTR); |
| sb->s_dirt = 1; |
| ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh); |
| } |
| } |
| |
| /* |
| * Release the xattr block BH: If the reference count is > 1, decrement |
| * it; otherwise free the block. |
| */ |
| static void |
| ext4_xattr_release_block(handle_t *handle, struct inode *inode, |
| struct buffer_head *bh) |
| { |
| struct mb_cache_entry *ce = NULL; |
| int error = 0; |
| |
| ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr); |
| error = ext4_journal_get_write_access(handle, bh); |
| if (error) |
| goto out; |
| |
| lock_buffer(bh); |
| if (BHDR(bh)->h_refcount == cpu_to_le32(1)) { |
| ea_bdebug(bh, "refcount now=0; freeing"); |
| if (ce) |
| mb_cache_entry_free(ce); |
| get_bh(bh); |
| ext4_free_blocks(handle, inode, bh, 0, 1, |
| EXT4_FREE_BLOCKS_METADATA | |
| EXT4_FREE_BLOCKS_FORGET); |
| } else { |
| le32_add_cpu(&BHDR(bh)->h_refcount, -1); |
| error = ext4_handle_dirty_metadata(handle, inode, bh); |
| if (IS_SYNC(inode)) |
| ext4_handle_sync(handle); |
| vfs_dq_free_block(inode, 1); |
| ea_bdebug(bh, "refcount now=%d; releasing", |
| le32_to_cpu(BHDR(bh)->h_refcount)); |
| if (ce) |
| mb_cache_entry_release(ce); |
| } |
| unlock_buffer(bh); |
| out: |
| ext4_std_error(inode->i_sb, error); |
| return; |
| } |
| |
| /* |
| * Find the available free space for EAs. This also returns the total number of |
| * bytes used by EA entries. |
| */ |
| static size_t ext4_xattr_free_space(struct ext4_xattr_entry *last, |
| size_t *min_offs, void *base, int *total) |
| { |
| for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { |
| *total += EXT4_XATTR_LEN(last->e_name_len); |
| 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; |
| } |
| } |
| return (*min_offs - ((void *)last - base) - sizeof(__u32)); |
| } |
| |
| struct ext4_xattr_info { |
| int name_index; |
| const char *name; |
| const void *value; |
| size_t value_len; |
| }; |
| |
| struct ext4_xattr_search { |
| struct ext4_xattr_entry *first; |
| void *base; |
| void *end; |
| struct ext4_xattr_entry *here; |
| int not_found; |
| }; |
| |
| static int |
| ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) |
| { |
| struct ext4_xattr_entry *last; |
| size_t free, min_offs = s->end - s->base, name_len = strlen(i->name); |
| |
| /* Compute min_offs and last. */ |
| last = s->first; |
| for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { |
| 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; |
| } |
| } |
| free = min_offs - ((void *)last - s->base) - sizeof(__u32); |
| if (!s->not_found) { |
| if (!s->here->e_value_block && s->here->e_value_size) { |
| size_t size = le32_to_cpu(s->here->e_value_size); |
| free += EXT4_XATTR_SIZE(size); |
| } |
| free += EXT4_XATTR_LEN(name_len); |
| } |
| if (i->value) { |
| if (free < EXT4_XATTR_SIZE(i->value_len) || |
| free < EXT4_XATTR_LEN(name_len) + |
| EXT4_XATTR_SIZE(i->value_len)) |
| return -ENOSPC; |
| } |
| |
| if (i->value && s->not_found) { |
| /* Insert the new name. */ |
| size_t size = EXT4_XATTR_LEN(name_len); |
| size_t rest = (void *)last - (void *)s->here + sizeof(__u32); |
| memmove((void *)s->here + size, s->here, rest); |
| memset(s->here, 0, size); |
| s->here->e_name_index = i->name_index; |
| s->here->e_name_len = name_len; |
| memcpy(s->here->e_name, i->name, name_len); |
| } else { |
| if (!s->here->e_value_block && s->here->e_value_size) { |
| void *first_val = s->base + min_offs; |
| size_t offs = le16_to_cpu(s->here->e_value_offs); |
| void *val = s->base + offs; |
| size_t size = EXT4_XATTR_SIZE( |
| le32_to_cpu(s->here->e_value_size)); |
| |
| if (i->value && size == EXT4_XATTR_SIZE(i->value_len)) { |
| /* The old and the new value have the same |
| size. Just replace. */ |
| s->here->e_value_size = |
| cpu_to_le32(i->value_len); |
| memset(val + size - EXT4_XATTR_PAD, 0, |
| EXT4_XATTR_PAD); /* Clear pad bytes. */ |
| memcpy(val, i->value, i->value_len); |
| return 0; |
| } |
| |
| /* Remove the old value. */ |
| memmove(first_val + size, first_val, val - first_val); |
| memset(first_val, 0, size); |
| s->here->e_value_size = 0; |
| s->here->e_value_offs = 0; |
| min_offs += size; |
| |
| /* Adjust all value offsets. */ |
| last = s->first; |
| while (!IS_LAST_ENTRY(last)) { |
| size_t o = le16_to_cpu(last->e_value_offs); |
| if (!last->e_value_block && |
| last->e_value_size && o < offs) |
| last->e_value_offs = |
| cpu_to_le16(o + size); |
| last = EXT4_XATTR_NEXT(last); |
| } |
| } |
| if (!i->value) { |
| /* Remove the old name. */ |
| size_t size = EXT4_XATTR_LEN(name_len); |
| last = ENTRY((void *)last - size); |
| memmove(s->here, (void *)s->here + size, |
| (void *)last - (void *)s->here + sizeof(__u32)); |
| memset(last, 0, size); |
| } |
| } |
| |
| if (i->value) { |
| /* Insert the new value. */ |
| s->here->e_value_size = cpu_to_le32(i->value_len); |
| if (i->value_len) { |
| size_t size = EXT4_XATTR_SIZE(i->value_len); |
| void *val = s->base + min_offs - size; |
| s->here->e_value_offs = cpu_to_le16(min_offs - size); |
| memset(val + size - EXT4_XATTR_PAD, 0, |
| EXT4_XATTR_PAD); /* Clear the pad bytes. */ |
| memcpy(val, i->value, i->value_len); |
| } |
| } |
| return 0; |
| } |
| |
| struct ext4_xattr_block_find { |
| struct ext4_xattr_search s; |
| struct buffer_head *bh; |
| }; |
| |
| static int |
| ext4_xattr_block_find(struct inode *inode, struct ext4_xattr_info *i, |
| struct ext4_xattr_block_find *bs) |
| { |
| struct super_block *sb = inode->i_sb; |
| int error; |
| |
| ea_idebug(inode, "name=%d.%s, value=%p, value_len=%ld", |
| i->name_index, i->name, i->value, (long)i->value_len); |
| |
| if (EXT4_I(inode)->i_file_acl) { |
| /* The inode already has an extended attribute block. */ |
| bs->bh = sb_bread(sb, EXT4_I(inode)->i_file_acl); |
| error = -EIO; |
| if (!bs->bh) |
| goto cleanup; |
| ea_bdebug(bs->bh, "b_count=%d, refcount=%d", |
| atomic_read(&(bs->bh->b_count)), |
| le32_to_cpu(BHDR(bs->bh)->h_refcount)); |
| if (ext4_xattr_check_block(bs->bh)) { |
| ext4_error(sb, "inode %lu: bad block %llu", |
| inode->i_ino, EXT4_I(inode)->i_file_acl); |
| error = -EIO; |
| goto cleanup; |
| } |
| /* Find the named attribute. */ |
| bs->s.base = BHDR(bs->bh); |
| bs->s.first = BFIRST(bs->bh); |
| bs->s.end = bs->bh->b_data + bs->bh->b_size; |
| bs->s.here = bs->s.first; |
| error = ext4_xattr_find_entry(&bs->s.here, i->name_index, |
| i->name, bs->bh->b_size, 1); |
| if (error && error != -ENODATA) |
| goto cleanup; |
| bs->s.not_found = error; |
| } |
| error = 0; |
| |
| cleanup: |
| return error; |
| } |
| |
| static int |
| ext4_xattr_block_set(handle_t *handle, struct inode *inode, |
| struct ext4_xattr_info *i, |
| struct ext4_xattr_block_find *bs) |
| { |
| struct super_block *sb = inode->i_sb; |
| struct buffer_head *new_bh = NULL; |
| struct ext4_xattr_search *s = &bs->s; |
| struct mb_cache_entry *ce = NULL; |
| int error = 0; |
| |
| #define header(x) ((struct ext4_xattr_header *)(x)) |
| |
| if (i->value && i->value_len > sb->s_blocksize) |
| return -ENOSPC; |
| if (s->base) { |
| ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev, |
| bs->bh->b_blocknr); |
| error = ext4_journal_get_write_access(handle, bs->bh); |
| if (error) |
| goto cleanup; |
| lock_buffer(bs->bh); |
| |
| if (header(s->base)->h_refcount == cpu_to_le32(1)) { |
| if (ce) { |
| mb_cache_entry_free(ce); |
| ce = NULL; |
| } |
| ea_bdebug(bs->bh, "modifying in-place"); |
| error = ext4_xattr_set_entry(i, s); |
| if (!error) { |
| if (!IS_LAST_ENTRY(s->first)) |
| ext4_xattr_rehash(header(s->base), |
| s->here); |
| ext4_xattr_cache_insert(bs->bh); |
| } |
| unlock_buffer(bs->bh); |
| if (error == -EIO) |
| goto bad_block; |
| if (!error) |
| error = ext4_handle_dirty_metadata(handle, |
| inode, |
| bs->bh); |
| if (error) |
| goto cleanup; |
| goto inserted; |
| } else { |
| int offset = (char *)s->here - bs->bh->b_data; |
| |
| unlock_buffer(bs->bh); |
| jbd2_journal_release_buffer(handle, bs->bh); |
| if (ce) { |
| mb_cache_entry_release(ce); |
| ce = NULL; |
| } |
| ea_bdebug(bs->bh, "cloning"); |
| s->base = kmalloc(bs->bh->b_size, GFP_NOFS); |
| error = -ENOMEM; |
| if (s->base == NULL) |
| goto cleanup; |
| memcpy(s->base, BHDR(bs->bh), bs->bh->b_size); |
| s->first = ENTRY(header(s->base)+1); |
| header(s->base)->h_refcount = cpu_to_le32(1); |
| s->here = ENTRY(s->base + offset); |
| s->end = s->base + bs->bh->b_size; |
| } |
| } else { |
| /* Allocate a buffer where we construct the new block. */ |
| s->base = kzalloc(sb->s_blocksize, GFP_NOFS); |
| /* assert(header == s->base) */ |
| error = -ENOMEM; |
| if (s->base == NULL) |
| goto cleanup; |
| header(s->base)->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); |
| header(s->base)->h_blocks = cpu_to_le32(1); |
| header(s->base)->h_refcount = cpu_to_le32(1); |
| s->first = ENTRY(header(s->base)+1); |
| s->here = ENTRY(header(s->base)+1); |
| s->end = s->base + sb->s_blocksize; |
| } |
| |
| error = ext4_xattr_set_entry(i, s); |
| if (error == -EIO) |
| goto bad_block; |
| if (error) |
| goto cleanup; |
| if (!IS_LAST_ENTRY(s->first)) |
| ext4_xattr_rehash(header(s->base), s->here); |
| |
| inserted: |
| if (!IS_LAST_ENTRY(s->first)) { |
| new_bh = ext4_xattr_cache_find(inode, header(s->base), &ce); |
| if (new_bh) { |
| /* We found an identical block in the cache. */ |
| if (new_bh == bs->bh) |
| ea_bdebug(new_bh, "keeping"); |
| else { |
| /* The old block is released after updating |
| the inode. */ |
| error = -EDQUOT; |
| if (vfs_dq_alloc_block(inode, 1)) |
| goto cleanup; |
| error = ext4_journal_get_write_access(handle, |
| new_bh); |
| if (error) |
| goto cleanup_dquot; |
| lock_buffer(new_bh); |
| le32_add_cpu(&BHDR(new_bh)->h_refcount, 1); |
| ea_bdebug(new_bh, "reusing; refcount now=%d", |
| le32_to_cpu(BHDR(new_bh)->h_refcount)); |
| unlock_buffer(new_bh); |
| error = ext4_handle_dirty_metadata(handle, |
| inode, |
| new_bh); |
| if (error) |
| goto cleanup_dquot; |
| } |
| mb_cache_entry_release(ce); |
| ce = NULL; |
| } else if (bs->bh && s->base == bs->bh->b_data) { |
| /* We were modifying this block in-place. */ |
| ea_bdebug(bs->bh, "keeping this block"); |
| new_bh = bs->bh; |
| get_bh(new_bh); |
| } else { |
| /* We need to allocate a new block */ |
| ext4_fsblk_t goal, block; |
| |
| goal = ext4_group_first_block_no(sb, |
| EXT4_I(inode)->i_block_group); |
| |
| /* non-extent files can't have physical blocks past 2^32 */ |
| if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) |
| goal = goal & EXT4_MAX_BLOCK_FILE_PHYS; |
| |
| block = ext4_new_meta_blocks(handle, inode, |
| goal, NULL, &error); |
| if (error) |
| goto cleanup; |
| |
| if (!(EXT4_I(inode)->i_flags & EXT4_EXTENTS_FL)) |
| BUG_ON(block > EXT4_MAX_BLOCK_FILE_PHYS); |
| |
| ea_idebug(inode, "creating block %d", block); |
| |
| new_bh = sb_getblk(sb, block); |
| if (!new_bh) { |
| getblk_failed: |
| ext4_free_blocks(handle, inode, 0, block, 1, |
| EXT4_FREE_BLOCKS_METADATA); |
| error = -EIO; |
| goto cleanup; |
| } |
| lock_buffer(new_bh); |
| error = ext4_journal_get_create_access(handle, new_bh); |
| if (error) { |
| unlock_buffer(new_bh); |
| goto getblk_failed; |
| } |
| memcpy(new_bh->b_data, s->base, new_bh->b_size); |
| set_buffer_uptodate(new_bh); |
| unlock_buffer(new_bh); |
| ext4_xattr_cache_insert(new_bh); |
| error = ext4_handle_dirty_metadata(handle, |
| inode, new_bh); |
| if (error) |
| goto cleanup; |
| } |
| } |
| |
| /* Update the inode. */ |
| EXT4_I(inode)->i_file_acl = new_bh ? new_bh->b_blocknr : 0; |
| |
| /* Drop the previous xattr block. */ |
| if (bs->bh && bs->bh != new_bh) |
| ext4_xattr_release_block(handle, inode, bs->bh); |
| error = 0; |
| |
| cleanup: |
| if (ce) |
| mb_cache_entry_release(ce); |
| brelse(new_bh); |
| if (!(bs->bh && s->base == bs->bh->b_data)) |
| kfree(s->base); |
| |
| return error; |
| |
| cleanup_dquot: |
| vfs_dq_free_block(inode, 1); |
| goto cleanup; |
| |
| bad_block: |
| ext4_error(inode->i_sb, "inode %lu: bad block %llu", |
| inode->i_ino, EXT4_I(inode)->i_file_acl); |
| goto cleanup; |
| |
| #undef header |
| } |
| |
| struct ext4_xattr_ibody_find { |
| struct ext4_xattr_search s; |
| struct ext4_iloc iloc; |
| }; |
| |
| static int |
| ext4_xattr_ibody_find(struct inode *inode, struct ext4_xattr_info *i, |
| struct ext4_xattr_ibody_find *is) |
| { |
| struct ext4_xattr_ibody_header *header; |
| struct ext4_inode *raw_inode; |
| int error; |
| |
| if (EXT4_I(inode)->i_extra_isize == 0) |
| return 0; |
| raw_inode = ext4_raw_inode(&is->iloc); |
| header = IHDR(inode, raw_inode); |
| is->s.base = is->s.first = IFIRST(header); |
| is->s.here = is->s.first; |
| is->s.end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; |
| if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { |
| error = ext4_xattr_check_names(IFIRST(header), is->s.end); |
| if (error) |
| return error; |
| /* Find the named attribute. */ |
| error = ext4_xattr_find_entry(&is->s.here, i->name_index, |
| i->name, is->s.end - |
| (void *)is->s.base, 0); |
| if (error && error != -ENODATA) |
| return error; |
| is->s.not_found = error; |
| } |
| return 0; |
| } |
| |
| static int |
| ext4_xattr_ibody_set(handle_t *handle, struct inode *inode, |
| struct ext4_xattr_info *i, |
| struct ext4_xattr_ibody_find *is) |
| { |
| struct ext4_xattr_ibody_header *header; |
| struct ext4_xattr_search *s = &is->s; |
| int error; |
| |
| if (EXT4_I(inode)->i_extra_isize == 0) |
| return -ENOSPC; |
| error = ext4_xattr_set_entry(i, s); |
| if (error) |
| return error; |
| header = IHDR(inode, ext4_raw_inode(&is->iloc)); |
| if (!IS_LAST_ENTRY(s->first)) { |
| header->h_magic = cpu_to_le32(EXT4_XATTR_MAGIC); |
| ext4_set_inode_state(inode, EXT4_STATE_XATTR); |
| } else { |
| header->h_magic = cpu_to_le32(0); |
| ext4_clear_inode_state(inode, EXT4_STATE_XATTR); |
| } |
| return 0; |
| } |
| |
| /* |
| * ext4_xattr_set_handle() |
| * |
| * 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 |
| ext4_xattr_set_handle(handle_t *handle, struct inode *inode, int name_index, |
| const char *name, const void *value, size_t value_len, |
| int flags) |
| { |
| struct ext4_xattr_info i = { |
| .name_index = name_index, |
| .name = name, |
| .value = value, |
| .value_len = value_len, |
| |
| }; |
| struct ext4_xattr_ibody_find is = { |
| .s = { .not_found = -ENODATA, }, |
| }; |
| struct ext4_xattr_block_find bs = { |
| .s = { .not_found = -ENODATA, }, |
| }; |
| unsigned long no_expand; |
| int error; |
| |
| if (!name) |
| return -EINVAL; |
| if (strlen(name) > 255) |
| return -ERANGE; |
| down_write(&EXT4_I(inode)->xattr_sem); |
| no_expand = ext4_test_inode_state(inode, EXT4_STATE_NO_EXPAND); |
| ext4_set_inode_state(inode, EXT4_STATE_NO_EXPAND); |
| |
| error = ext4_get_inode_loc(inode, &is.iloc); |
| if (error) |
| goto cleanup; |
| |
| error = ext4_journal_get_write_access(handle, is.iloc.bh); |
| if (error) |
| goto cleanup; |
| |
| if (ext4_test_inode_state(inode, EXT4_STATE_NEW)) { |
| struct ext4_inode *raw_inode = ext4_raw_inode(&is.iloc); |
| memset(raw_inode, 0, EXT4_SB(inode->i_sb)->s_inode_size); |
| ext4_clear_inode_state(inode, EXT4_STATE_NEW); |
| } |
| |
| error = ext4_xattr_ibody_find(inode, &i, &is); |
| if (error) |
| goto cleanup; |
| if (is.s.not_found) |
| error = ext4_xattr_block_find(inode, &i, &bs); |
| if (error) |
| goto cleanup; |
| if (is.s.not_found && bs.s.not_found) { |
| error = -ENODATA; |
| if (flags & XATTR_REPLACE) |
| goto cleanup; |
| error = 0; |
| if (!value) |
| goto cleanup; |
| } else { |
| error = -EEXIST; |
| if (flags & XATTR_CREATE) |
| goto cleanup; |
| } |
| if (!value) { |
| if (!is.s.not_found) |
| error = ext4_xattr_ibody_set(handle, inode, &i, &is); |
| else if (!bs.s.not_found) |
| error = ext4_xattr_block_set(handle, inode, &i, &bs); |
| } else { |
| error = ext4_xattr_ibody_set(handle, inode, &i, &is); |
| if (!error && !bs.s.not_found) { |
| i.value = NULL; |
| error = ext4_xattr_block_set(handle, inode, &i, &bs); |
| } else if (error == -ENOSPC) { |
| if (EXT4_I(inode)->i_file_acl && !bs.s.base) { |
| error = ext4_xattr_block_find(inode, &i, &bs); |
| if (error) |
| goto cleanup; |
| } |
| error = ext4_xattr_block_set(handle, inode, &i, &bs); |
| if (error) |
| goto cleanup; |
| if (!is.s.not_found) { |
| i.value = NULL; |
| error = ext4_xattr_ibody_set(handle, inode, &i, |
| &is); |
| } |
| } |
| } |
| if (!error) { |
| ext4_xattr_update_super_block(handle, inode->i_sb); |
| inode->i_ctime = ext4_current_time(inode); |
| if (!value) |
| ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); |
| error = ext4_mark_iloc_dirty(handle, inode, &is.iloc); |
| /* |
| * The bh is consumed by ext4_mark_iloc_dirty, even with |
| * error != 0. |
| */ |
| is.iloc.bh = NULL; |
| if (IS_SYNC(inode)) |
| ext4_handle_sync(handle); |
| } |
| |
| cleanup: |
| brelse(is.iloc.bh); |
| brelse(bs.bh); |
| if (no_expand == 0) |
| ext4_clear_inode_state(inode, EXT4_STATE_NO_EXPAND); |
| up_write(&EXT4_I(inode)->xattr_sem); |
| return error; |
| } |
| |
| /* |
| * ext4_xattr_set() |
| * |
| * Like ext4_xattr_set_handle, but start from an inode. This extended |
| * attribute modification is a filesystem transaction by itself. |
| * |
| * Returns 0, or a negative error number on failure. |
| */ |
| int |
| ext4_xattr_set(struct inode *inode, int name_index, const char *name, |
| const void *value, size_t value_len, int flags) |
| { |
| handle_t *handle; |
| int error, retries = 0; |
| |
| retry: |
| handle = ext4_journal_start(inode, EXT4_DATA_TRANS_BLOCKS(inode->i_sb)); |
| if (IS_ERR(handle)) { |
| error = PTR_ERR(handle); |
| } else { |
| int error2; |
| |
| error = ext4_xattr_set_handle(handle, inode, name_index, name, |
| value, value_len, flags); |
| error2 = ext4_journal_stop(handle); |
| if (error == -ENOSPC && |
| ext4_should_retry_alloc(inode->i_sb, &retries)) |
| goto retry; |
| if (error == 0) |
| error = error2; |
| } |
| |
| return error; |
| } |
| |
| /* |
| * Shift the EA entries in the inode to create space for the increased |
| * i_extra_isize. |
| */ |
| static void ext4_xattr_shift_entries(struct ext4_xattr_entry *entry, |
| int value_offs_shift, void *to, |
| void *from, size_t n, int blocksize) |
| { |
| struct ext4_xattr_entry *last = entry; |
| int new_offs; |
| |
| /* Adjust the value offsets of the entries */ |
| for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { |
| if (!last->e_value_block && last->e_value_size) { |
| new_offs = le16_to_cpu(last->e_value_offs) + |
| value_offs_shift; |
| BUG_ON(new_offs + le32_to_cpu(last->e_value_size) |
| > blocksize); |
| last->e_value_offs = cpu_to_le16(new_offs); |
| } |
| } |
| /* Shift the entries by n bytes */ |
| memmove(to, from, n); |
| } |
| |
| /* |
| * Expand an inode by new_extra_isize bytes when EAs are present. |
| * Returns 0 on success or negative error number on failure. |
| */ |
| int ext4_expand_extra_isize_ea(struct inode *inode, int new_extra_isize, |
| struct ext4_inode *raw_inode, handle_t *handle) |
| { |
| struct ext4_xattr_ibody_header *header; |
| struct ext4_xattr_entry *entry, *last, *first; |
| struct buffer_head *bh = NULL; |
| struct ext4_xattr_ibody_find *is = NULL; |
| struct ext4_xattr_block_find *bs = NULL; |
| char *buffer = NULL, *b_entry_name = NULL; |
| size_t min_offs, free; |
| int total_ino, total_blk; |
| void *base, *start, *end; |
| int extra_isize = 0, error = 0, tried_min_extra_isize = 0; |
| int s_min_extra_isize = le16_to_cpu(EXT4_SB(inode->i_sb)->s_es->s_min_extra_isize); |
| |
| down_write(&EXT4_I(inode)->xattr_sem); |
| retry: |
| if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) { |
| up_write(&EXT4_I(inode)->xattr_sem); |
| return 0; |
| } |
| |
| header = IHDR(inode, raw_inode); |
| entry = IFIRST(header); |
| |
| /* |
| * Check if enough free space is available in the inode to shift the |
| * entries ahead by new_extra_isize. |
| */ |
| |
| base = start = entry; |
| end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; |
| min_offs = end - base; |
| last = entry; |
| total_ino = sizeof(struct ext4_xattr_ibody_header); |
| |
| free = ext4_xattr_free_space(last, &min_offs, base, &total_ino); |
| if (free >= new_extra_isize) { |
| entry = IFIRST(header); |
| ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize |
| - new_extra_isize, (void *)raw_inode + |
| EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, |
| (void *)header, total_ino, |
| inode->i_sb->s_blocksize); |
| EXT4_I(inode)->i_extra_isize = new_extra_isize; |
| error = 0; |
| goto cleanup; |
| } |
| |
| /* |
| * Enough free space isn't available in the inode, check if |
| * EA block can hold new_extra_isize bytes. |
| */ |
| if (EXT4_I(inode)->i_file_acl) { |
| bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); |
| error = -EIO; |
| if (!bh) |
| goto cleanup; |
| if (ext4_xattr_check_block(bh)) { |
| ext4_error(inode->i_sb, "inode %lu: bad block %llu", |
| inode->i_ino, EXT4_I(inode)->i_file_acl); |
| error = -EIO; |
| goto cleanup; |
| } |
| base = BHDR(bh); |
| first = BFIRST(bh); |
| end = bh->b_data + bh->b_size; |
| min_offs = end - base; |
| free = ext4_xattr_free_space(first, &min_offs, base, |
| &total_blk); |
| if (free < new_extra_isize) { |
| if (!tried_min_extra_isize && s_min_extra_isize) { |
| tried_min_extra_isize++; |
| new_extra_isize = s_min_extra_isize; |
| brelse(bh); |
| goto retry; |
| } |
| error = -1; |
| goto cleanup; |
| } |
| } else { |
| free = inode->i_sb->s_blocksize; |
| } |
| |
| while (new_extra_isize > 0) { |
| size_t offs, size, entry_size; |
| struct ext4_xattr_entry *small_entry = NULL; |
| struct ext4_xattr_info i = { |
| .value = NULL, |
| .value_len = 0, |
| }; |
| unsigned int total_size; /* EA entry size + value size */ |
| unsigned int shift_bytes; /* No. of bytes to shift EAs by? */ |
| unsigned int min_total_size = ~0U; |
| |
| is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); |
| bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); |
| if (!is || !bs) { |
| error = -ENOMEM; |
| goto cleanup; |
| } |
| |
| is->s.not_found = -ENODATA; |
| bs->s.not_found = -ENODATA; |
| is->iloc.bh = NULL; |
| bs->bh = NULL; |
| |
| last = IFIRST(header); |
| /* Find the entry best suited to be pushed into EA block */ |
| entry = NULL; |
| for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { |
| total_size = |
| EXT4_XATTR_SIZE(le32_to_cpu(last->e_value_size)) + |
| EXT4_XATTR_LEN(last->e_name_len); |
| if (total_size <= free && total_size < min_total_size) { |
| if (total_size < new_extra_isize) { |
| small_entry = last; |
| } else { |
| entry = last; |
| min_total_size = total_size; |
| } |
| } |
| } |
| |
| if (entry == NULL) { |
| if (small_entry) { |
| entry = small_entry; |
| } else { |
| if (!tried_min_extra_isize && |
| s_min_extra_isize) { |
| tried_min_extra_isize++; |
| new_extra_isize = s_min_extra_isize; |
| goto retry; |
| } |
| error = -1; |
| goto cleanup; |
| } |
| } |
| offs = le16_to_cpu(entry->e_value_offs); |
| size = le32_to_cpu(entry->e_value_size); |
| entry_size = EXT4_XATTR_LEN(entry->e_name_len); |
| i.name_index = entry->e_name_index, |
| buffer = kmalloc(EXT4_XATTR_SIZE(size), GFP_NOFS); |
| b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); |
| if (!buffer || !b_entry_name) { |
| error = -ENOMEM; |
| goto cleanup; |
| } |
| /* Save the entry name and the entry value */ |
| memcpy(buffer, (void *)IFIRST(header) + offs, |
| EXT4_XATTR_SIZE(size)); |
| memcpy(b_entry_name, entry->e_name, entry->e_name_len); |
| b_entry_name[entry->e_name_len] = '\0'; |
| i.name = b_entry_name; |
| |
| error = ext4_get_inode_loc(inode, &is->iloc); |
| if (error) |
| goto cleanup; |
| |
| error = ext4_xattr_ibody_find(inode, &i, is); |
| if (error) |
| goto cleanup; |
| |
| /* Remove the chosen entry from the inode */ |
| error = ext4_xattr_ibody_set(handle, inode, &i, is); |
| |
| entry = IFIRST(header); |
| if (entry_size + EXT4_XATTR_SIZE(size) >= new_extra_isize) |
| shift_bytes = new_extra_isize; |
| else |
| shift_bytes = entry_size + size; |
| /* Adjust the offsets and shift the remaining entries ahead */ |
| ext4_xattr_shift_entries(entry, EXT4_I(inode)->i_extra_isize - |
| shift_bytes, (void *)raw_inode + |
| EXT4_GOOD_OLD_INODE_SIZE + extra_isize + shift_bytes, |
| (void *)header, total_ino - entry_size, |
| inode->i_sb->s_blocksize); |
| |
| extra_isize += shift_bytes; |
| new_extra_isize -= shift_bytes; |
| EXT4_I(inode)->i_extra_isize = extra_isize; |
| |
| i.name = b_entry_name; |
| i.value = buffer; |
| i.value_len = size; |
| error = ext4_xattr_block_find(inode, &i, bs); |
| if (error) |
| goto cleanup; |
| |
| /* Add entry which was removed from the inode into the block */ |
| error = ext4_xattr_block_set(handle, inode, &i, bs); |
| if (error) |
| goto cleanup; |
| kfree(b_entry_name); |
| kfree(buffer); |
| b_entry_name = NULL; |
| buffer = NULL; |
| brelse(is->iloc.bh); |
| kfree(is); |
| kfree(bs); |
| } |
| brelse(bh); |
| up_write(&EXT4_I(inode)->xattr_sem); |
| return 0; |
| |
| cleanup: |
| kfree(b_entry_name); |
| kfree(buffer); |
| if (is) |
| brelse(is->iloc.bh); |
| kfree(is); |
| kfree(bs); |
| brelse(bh); |
| up_write(&EXT4_I(inode)->xattr_sem); |
| return error; |
| } |
| |
| |
| |
| /* |
| * ext4_xattr_delete_inode() |
| * |
| * Free extended attribute resources associated with this inode. This |
| * is called immediately before an inode is freed. We have exclusive |
| * access to the inode. |
| */ |
| void |
| ext4_xattr_delete_inode(handle_t *handle, struct inode *inode) |
| { |
| struct buffer_head *bh = NULL; |
| |
| if (!EXT4_I(inode)->i_file_acl) |
| goto cleanup; |
| bh = sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl); |
| if (!bh) { |
| ext4_error(inode->i_sb, "inode %lu: block %llu read error", |
| inode->i_ino, EXT4_I(inode)->i_file_acl); |
| goto cleanup; |
| } |
| if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || |
| BHDR(bh)->h_blocks != cpu_to_le32(1)) { |
| ext4_error(inode->i_sb, "inode %lu: bad block %llu", |
| inode->i_ino, EXT4_I(inode)->i_file_acl); |
| goto cleanup; |
| } |
| ext4_xattr_release_block(handle, inode, bh); |
| EXT4_I(inode)->i_file_acl = 0; |
| |
| cleanup: |
| brelse(bh); |
| } |
| |
| /* |
| * ext4_xattr_put_super() |
| * |
| * This is called when a file system is unmounted. |
| */ |
| void |
| ext4_xattr_put_super(struct super_block *sb) |
| { |
| mb_cache_shrink(sb->s_bdev); |
| } |
| |
| /* |
| * ext4_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 void |
| ext4_xattr_cache_insert(struct buffer_head *bh) |
| { |
| __u32 hash = le32_to_cpu(BHDR(bh)->h_hash); |
| struct mb_cache_entry *ce; |
| int error; |
| |
| ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS); |
| if (!ce) { |
| ea_bdebug(bh, "out of memory"); |
| return; |
| } |
| 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"); |
| error = 0; |
| } |
| } else { |
| ea_bdebug(bh, "inserting [%x]", (int)hash); |
| mb_cache_entry_release(ce); |
| } |
| } |
| |
| /* |
| * ext4_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 |
| ext4_xattr_cmp(struct ext4_xattr_header *header1, |
| struct ext4_xattr_header *header2) |
| { |
| struct ext4_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 = EXT4_XATTR_NEXT(entry1); |
| entry2 = EXT4_XATTR_NEXT(entry2); |
| } |
| if (!IS_LAST_ENTRY(entry2)) |
| return 1; |
| return 0; |
| } |
| |
| /* |
| * ext4_xattr_cache_find() |
| * |
| * Find an identical extended attribute block. |
| * |
| * Returns a pointer to the block found, or NULL if such a block was |
| * not found or an error occurred. |
| */ |
| static struct buffer_head * |
| ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header, |
| struct mb_cache_entry **pce) |
| { |
| __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(ext4_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) { |
| ext4_error(inode->i_sb, |
| "inode %lu: block %lu read error", |
| inode->i_ino, (unsigned long) ce->e_block); |
| } else if (le32_to_cpu(BHDR(bh)->h_refcount) >= |
| EXT4_XATTR_REFCOUNT_MAX) { |
| ea_idebug(inode, "block %lu refcount %d>=%d", |
| (unsigned long) ce->e_block, |
| le32_to_cpu(BHDR(bh)->h_refcount), |
| EXT4_XATTR_REFCOUNT_MAX); |
| } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { |
| *pce = ce; |
| return 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 |
| |
| /* |
| * ext4_xattr_hash_entry() |
| * |
| * Compute the hash of an extended attribute. |
| */ |
| static inline void ext4_xattr_hash_entry(struct ext4_xattr_header *header, |
| struct ext4_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) + |
| EXT4_XATTR_ROUND) >> EXT4_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 |
| |
| /* |
| * ext4_xattr_rehash() |
| * |
| * Re-compute the extended attribute hash value after an entry has changed. |
| */ |
| static void ext4_xattr_rehash(struct ext4_xattr_header *header, |
| struct ext4_xattr_entry *entry) |
| { |
| struct ext4_xattr_entry *here; |
| __u32 hash = 0; |
| |
| ext4_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 = EXT4_XATTR_NEXT(here); |
| } |
| header->h_hash = cpu_to_le32(hash); |
| } |
| |
| #undef BLOCK_HASH_SHIFT |
| |
| int __init |
| init_ext4_xattr(void) |
| { |
| ext4_xattr_cache = mb_cache_create("ext4_xattr", NULL, |
| sizeof(struct mb_cache_entry) + |
| sizeof(((struct mb_cache_entry *) 0)->e_indexes[0]), 1, 6); |
| if (!ext4_xattr_cache) |
| return -ENOMEM; |
| return 0; |
| } |
| |
| void |
| exit_ext4_xattr(void) |
| { |
| if (ext4_xattr_cache) |
| mb_cache_destroy(ext4_xattr_cache); |
| ext4_xattr_cache = NULL; |
| } |