diff options
Diffstat (limited to 'fs/ext4/xattr.c')
| -rw-r--r-- | fs/ext4/xattr.c | 3165 |
1 files changed, 3165 insertions, 0 deletions
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c new file mode 100644 index 000000000..eaed9fd2f --- /dev/null +++ b/fs/ext4/xattr.c @@ -0,0 +1,3165 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * 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/iversion.h> +#include "ext4_jbd2.h" +#include "ext4.h" +#include "xattr.h" +#include "acl.h" + +#ifdef EXT4_XATTR_DEBUG +# define ea_idebug(inode, fmt, ...) \ + printk(KERN_DEBUG "inode %s:%lu: " fmt "\n", \ + inode->i_sb->s_id, inode->i_ino, ##__VA_ARGS__) +# define ea_bdebug(bh, fmt, ...) \ + printk(KERN_DEBUG "block %pg:%lu: " fmt "\n", \ + bh->b_bdev, (unsigned long)bh->b_blocknr, ##__VA_ARGS__) +#else +# define ea_idebug(inode, fmt, ...) no_printk(fmt, ##__VA_ARGS__) +# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__) +#endif + +static void ext4_xattr_block_cache_insert(struct mb_cache *, + struct buffer_head *); +static struct buffer_head * +ext4_xattr_block_cache_find(struct inode *, struct ext4_xattr_header *, + struct mb_cache_entry **); +static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value, + size_t value_count); +static void ext4_xattr_rehash(struct ext4_xattr_header *); + +static const struct xattr_handler * const ext4_xattr_handler_map[] = { + [EXT4_XATTR_INDEX_USER] = &ext4_xattr_user_handler, +#ifdef CONFIG_EXT4_FS_POSIX_ACL + [EXT4_XATTR_INDEX_POSIX_ACL_ACCESS] = &posix_acl_access_xattr_handler, + [EXT4_XATTR_INDEX_POSIX_ACL_DEFAULT] = &posix_acl_default_xattr_handler, +#endif + [EXT4_XATTR_INDEX_TRUSTED] = &ext4_xattr_trusted_handler, +#ifdef CONFIG_EXT4_FS_SECURITY + [EXT4_XATTR_INDEX_SECURITY] = &ext4_xattr_security_handler, +#endif + [EXT4_XATTR_INDEX_HURD] = &ext4_xattr_hurd_handler, +}; + +const struct xattr_handler *ext4_xattr_handlers[] = { + &ext4_xattr_user_handler, + &ext4_xattr_trusted_handler, +#ifdef CONFIG_EXT4_FS_POSIX_ACL + &posix_acl_access_xattr_handler, + &posix_acl_default_xattr_handler, +#endif +#ifdef CONFIG_EXT4_FS_SECURITY + &ext4_xattr_security_handler, +#endif + &ext4_xattr_hurd_handler, + NULL +}; + +#define EA_BLOCK_CACHE(inode) (((struct ext4_sb_info *) \ + inode->i_sb->s_fs_info)->s_ea_block_cache) + +#define EA_INODE_CACHE(inode) (((struct ext4_sb_info *) \ + inode->i_sb->s_fs_info)->s_ea_inode_cache) + +static int +ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array, + struct inode *inode); + +#ifdef CONFIG_LOCKDEP +void ext4_xattr_inode_set_class(struct inode *ea_inode) +{ + struct ext4_inode_info *ei = EXT4_I(ea_inode); + + lockdep_set_subclass(&ea_inode->i_rwsem, 1); + (void) ei; /* shut up clang warning if !CONFIG_LOCKDEP */ + lockdep_set_subclass(&ei->i_data_sem, I_DATA_SEM_EA); +} +#endif + +static __le32 ext4_xattr_block_csum(struct inode *inode, + sector_t block_nr, + struct ext4_xattr_header *hdr) +{ + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + __u32 csum; + __le64 dsk_block_nr = cpu_to_le64(block_nr); + __u32 dummy_csum = 0; + int offset = offsetof(struct ext4_xattr_header, h_checksum); + + csum = ext4_chksum(sbi, sbi->s_csum_seed, (__u8 *)&dsk_block_nr, + sizeof(dsk_block_nr)); + csum = ext4_chksum(sbi, csum, (__u8 *)hdr, offset); + csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum)); + offset += sizeof(dummy_csum); + csum = ext4_chksum(sbi, csum, (__u8 *)hdr + offset, + EXT4_BLOCK_SIZE(inode->i_sb) - offset); + + return cpu_to_le32(csum); +} + +static int ext4_xattr_block_csum_verify(struct inode *inode, + struct buffer_head *bh) +{ + struct ext4_xattr_header *hdr = BHDR(bh); + int ret = 1; + + if (ext4_has_metadata_csum(inode->i_sb)) { + lock_buffer(bh); + ret = (hdr->h_checksum == ext4_xattr_block_csum(inode, + bh->b_blocknr, hdr)); + unlock_buffer(bh); + } + return ret; +} + +static void ext4_xattr_block_csum_set(struct inode *inode, + struct buffer_head *bh) +{ + if (ext4_has_metadata_csum(inode->i_sb)) + BHDR(bh)->h_checksum = ext4_xattr_block_csum(inode, + bh->b_blocknr, BHDR(bh)); +} + +static inline const struct xattr_handler * +ext4_xattr_handler(int name_index) +{ + const 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; +} + +static int +ext4_xattr_check_entries(struct ext4_xattr_entry *entry, void *end, + void *value_start) +{ + struct ext4_xattr_entry *e = entry; + + /* Find the end of the names list */ + while (!IS_LAST_ENTRY(e)) { + struct ext4_xattr_entry *next = EXT4_XATTR_NEXT(e); + if ((void *)next >= end) + return -EFSCORRUPTED; + if (strnlen(e->e_name, e->e_name_len) != e->e_name_len) + return -EFSCORRUPTED; + e = next; + } + + /* Check the values */ + while (!IS_LAST_ENTRY(entry)) { + u32 size = le32_to_cpu(entry->e_value_size); + + if (size > EXT4_XATTR_SIZE_MAX) + return -EFSCORRUPTED; + + if (size != 0 && entry->e_value_inum == 0) { + u16 offs = le16_to_cpu(entry->e_value_offs); + void *value; + + /* + * The value cannot overlap the names, and the value + * with padding cannot extend beyond 'end'. Check both + * the padded and unpadded sizes, since the size may + * overflow to 0 when adding padding. + */ + if (offs > end - value_start) + return -EFSCORRUPTED; + value = value_start + offs; + if (value < (void *)e + sizeof(u32) || + size > end - value || + EXT4_XATTR_SIZE(size) > end - value) + return -EFSCORRUPTED; + } + entry = EXT4_XATTR_NEXT(entry); + } + + return 0; +} + +static inline int +__ext4_xattr_check_block(struct inode *inode, struct buffer_head *bh, + const char *function, unsigned int line) +{ + int error = -EFSCORRUPTED; + + if (BHDR(bh)->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC) || + BHDR(bh)->h_blocks != cpu_to_le32(1)) + goto errout; + if (buffer_verified(bh)) + return 0; + + error = -EFSBADCRC; + if (!ext4_xattr_block_csum_verify(inode, bh)) + goto errout; + error = ext4_xattr_check_entries(BFIRST(bh), bh->b_data + bh->b_size, + bh->b_data); +errout: + if (error) + __ext4_error_inode(inode, function, line, 0, -error, + "corrupted xattr block %llu", + (unsigned long long) bh->b_blocknr); + else + set_buffer_verified(bh); + return error; +} + +#define ext4_xattr_check_block(inode, bh) \ + __ext4_xattr_check_block((inode), (bh), __func__, __LINE__) + + +static int +__xattr_check_inode(struct inode *inode, struct ext4_xattr_ibody_header *header, + void *end, const char *function, unsigned int line) +{ + int error = -EFSCORRUPTED; + + if (end - (void *)header < sizeof(*header) + sizeof(u32) || + (header->h_magic != cpu_to_le32(EXT4_XATTR_MAGIC))) + goto errout; + error = ext4_xattr_check_entries(IFIRST(header), end, IFIRST(header)); +errout: + if (error) + __ext4_error_inode(inode, function, line, 0, -error, + "corrupted in-inode xattr"); + return error; +} + +#define xattr_check_inode(inode, header, end) \ + __xattr_check_inode((inode), (header), (end), __func__, __LINE__) + +static int +xattr_find_entry(struct inode *inode, struct ext4_xattr_entry **pentry, + void *end, int name_index, const char *name, int sorted) +{ + struct ext4_xattr_entry *entry, *next; + size_t name_len; + int cmp = 1; + + if (name == NULL) + return -EINVAL; + name_len = strlen(name); + for (entry = *pentry; !IS_LAST_ENTRY(entry); entry = next) { + next = EXT4_XATTR_NEXT(entry); + if ((void *) next >= end) { + EXT4_ERROR_INODE(inode, "corrupted xattr entries"); + return -EFSCORRUPTED; + } + 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; + return cmp ? -ENODATA : 0; +} + +static u32 +ext4_xattr_inode_hash(struct ext4_sb_info *sbi, const void *buffer, size_t size) +{ + return ext4_chksum(sbi, sbi->s_csum_seed, buffer, size); +} + +static u64 ext4_xattr_inode_get_ref(struct inode *ea_inode) +{ + return ((u64)ea_inode->i_ctime.tv_sec << 32) | + (u32) inode_peek_iversion_raw(ea_inode); +} + +static void ext4_xattr_inode_set_ref(struct inode *ea_inode, u64 ref_count) +{ + ea_inode->i_ctime.tv_sec = (u32)(ref_count >> 32); + inode_set_iversion_raw(ea_inode, ref_count & 0xffffffff); +} + +static u32 ext4_xattr_inode_get_hash(struct inode *ea_inode) +{ + return (u32)ea_inode->i_atime.tv_sec; +} + +static void ext4_xattr_inode_set_hash(struct inode *ea_inode, u32 hash) +{ + ea_inode->i_atime.tv_sec = hash; +} + +/* + * Read the EA value from an inode. + */ +static int ext4_xattr_inode_read(struct inode *ea_inode, void *buf, size_t size) +{ + int blocksize = 1 << ea_inode->i_blkbits; + int bh_count = (size + blocksize - 1) >> ea_inode->i_blkbits; + int tail_size = (size % blocksize) ?: blocksize; + struct buffer_head *bhs_inline[8]; + struct buffer_head **bhs = bhs_inline; + int i, ret; + + if (bh_count > ARRAY_SIZE(bhs_inline)) { + bhs = kmalloc_array(bh_count, sizeof(*bhs), GFP_NOFS); + if (!bhs) + return -ENOMEM; + } + + ret = ext4_bread_batch(ea_inode, 0 /* block */, bh_count, + true /* wait */, bhs); + if (ret) + goto free_bhs; + + for (i = 0; i < bh_count; i++) { + /* There shouldn't be any holes in ea_inode. */ + if (!bhs[i]) { + ret = -EFSCORRUPTED; + goto put_bhs; + } + memcpy((char *)buf + blocksize * i, bhs[i]->b_data, + i < bh_count - 1 ? blocksize : tail_size); + } + ret = 0; +put_bhs: + for (i = 0; i < bh_count; i++) + brelse(bhs[i]); +free_bhs: + if (bhs != bhs_inline) + kfree(bhs); + return ret; +} + +#define EXT4_XATTR_INODE_GET_PARENT(inode) ((__u32)(inode)->i_mtime.tv_sec) + +static int ext4_xattr_inode_iget(struct inode *parent, unsigned long ea_ino, + u32 ea_inode_hash, struct inode **ea_inode) +{ + struct inode *inode; + int err; + + /* + * We have to check for this corruption early as otherwise + * iget_locked() could wait indefinitely for the state of our + * parent inode. + */ + if (parent->i_ino == ea_ino) { + ext4_error(parent->i_sb, + "Parent and EA inode have the same ino %lu", ea_ino); + return -EFSCORRUPTED; + } + + inode = ext4_iget(parent->i_sb, ea_ino, EXT4_IGET_EA_INODE); + if (IS_ERR(inode)) { + err = PTR_ERR(inode); + ext4_error(parent->i_sb, + "error while reading EA inode %lu err=%d", ea_ino, + err); + return err; + } + ext4_xattr_inode_set_class(inode); + + /* + * Check whether this is an old Lustre-style xattr inode. Lustre + * implementation does not have hash validation, rather it has a + * backpointer from ea_inode to the parent inode. + */ + if (ea_inode_hash != ext4_xattr_inode_get_hash(inode) && + EXT4_XATTR_INODE_GET_PARENT(inode) == parent->i_ino && + inode->i_generation == parent->i_generation) { + ext4_set_inode_state(inode, EXT4_STATE_LUSTRE_EA_INODE); + ext4_xattr_inode_set_ref(inode, 1); + } else { + inode_lock(inode); + inode->i_flags |= S_NOQUOTA; + inode_unlock(inode); + } + + *ea_inode = inode; + return 0; +} + +/* Remove entry from mbcache when EA inode is getting evicted */ +void ext4_evict_ea_inode(struct inode *inode) +{ + struct mb_cache_entry *oe; + + if (!EA_INODE_CACHE(inode)) + return; + /* Wait for entry to get unused so that we can remove it */ + while ((oe = mb_cache_entry_delete_or_get(EA_INODE_CACHE(inode), + ext4_xattr_inode_get_hash(inode), inode->i_ino))) { + mb_cache_entry_wait_unused(oe); + mb_cache_entry_put(EA_INODE_CACHE(inode), oe); + } +} + +static int +ext4_xattr_inode_verify_hashes(struct inode *ea_inode, + struct ext4_xattr_entry *entry, void *buffer, + size_t size) +{ + u32 hash; + + /* Verify stored hash matches calculated hash. */ + hash = ext4_xattr_inode_hash(EXT4_SB(ea_inode->i_sb), buffer, size); + if (hash != ext4_xattr_inode_get_hash(ea_inode)) + return -EFSCORRUPTED; + + if (entry) { + __le32 e_hash, tmp_data; + + /* Verify entry hash. */ + tmp_data = cpu_to_le32(hash); + e_hash = ext4_xattr_hash_entry(entry->e_name, entry->e_name_len, + &tmp_data, 1); + if (e_hash != entry->e_hash) + return -EFSCORRUPTED; + } + return 0; +} + +/* + * Read xattr value from the EA inode. + */ +static int +ext4_xattr_inode_get(struct inode *inode, struct ext4_xattr_entry *entry, + void *buffer, size_t size) +{ + struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode); + struct inode *ea_inode; + int err; + + err = ext4_xattr_inode_iget(inode, le32_to_cpu(entry->e_value_inum), + le32_to_cpu(entry->e_hash), &ea_inode); + if (err) { + ea_inode = NULL; + goto out; + } + + if (i_size_read(ea_inode) != size) { + ext4_warning_inode(ea_inode, + "ea_inode file size=%llu entry size=%zu", + i_size_read(ea_inode), size); + err = -EFSCORRUPTED; + goto out; + } + + err = ext4_xattr_inode_read(ea_inode, buffer, size); + if (err) + goto out; + + if (!ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) { + err = ext4_xattr_inode_verify_hashes(ea_inode, entry, buffer, + size); + if (err) { + ext4_warning_inode(ea_inode, + "EA inode hash validation failed"); + goto out; + } + + if (ea_inode_cache) + mb_cache_entry_create(ea_inode_cache, GFP_NOFS, + ext4_xattr_inode_get_hash(ea_inode), + ea_inode->i_ino, true /* reusable */); + } +out: + iput(ea_inode); + return err; +} + +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; + void *end; + int error; + struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode); + + ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", + name_index, name, buffer, (long)buffer_size); + + if (!EXT4_I(inode)->i_file_acl) + return -ENODATA; + ea_idebug(inode, "reading block %llu", + (unsigned long long)EXT4_I(inode)->i_file_acl); + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) + return PTR_ERR(bh); + ea_bdebug(bh, "b_count=%d, refcount=%d", + atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); + error = ext4_xattr_check_block(inode, bh); + if (error) + goto cleanup; + ext4_xattr_block_cache_insert(ea_block_cache, bh); + entry = BFIRST(bh); + end = bh->b_data + bh->b_size; + error = xattr_find_entry(inode, &entry, end, name_index, name, 1); + if (error) + goto cleanup; + size = le32_to_cpu(entry->e_value_size); + error = -ERANGE; + if (unlikely(size > EXT4_XATTR_SIZE_MAX)) + goto cleanup; + if (buffer) { + if (size > buffer_size) + goto cleanup; + if (entry->e_value_inum) { + error = ext4_xattr_inode_get(inode, entry, buffer, + size); + if (error) + goto cleanup; + } else { + u16 offset = le16_to_cpu(entry->e_value_offs); + void *p = bh->b_data + offset; + + if (unlikely(p + size > end)) + goto cleanup; + memcpy(buffer, p, size); + } + } + error = size; + +cleanup: + brelse(bh); + return error; +} + +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); + end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; + error = xattr_check_inode(inode, header, end); + if (error) + goto cleanup; + entry = IFIRST(header); + error = xattr_find_entry(inode, &entry, end, name_index, name, 0); + if (error) + goto cleanup; + size = le32_to_cpu(entry->e_value_size); + error = -ERANGE; + if (unlikely(size > EXT4_XATTR_SIZE_MAX)) + goto cleanup; + if (buffer) { + if (size > buffer_size) + goto cleanup; + if (entry->e_value_inum) { + error = ext4_xattr_inode_get(inode, entry, buffer, + size); + if (error) + goto cleanup; + } else { + u16 offset = le16_to_cpu(entry->e_value_offs); + void *p = (void *)IFIRST(header) + offset; + + if (unlikely(p + size > end)) + goto cleanup; + memcpy(buffer, p, 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; + + if (unlikely(ext4_forced_shutdown(EXT4_SB(inode->i_sb)))) + return -EIO; + + if (strlen(name) > 255) + return -ERANGE; + + 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)) { + const struct xattr_handler *handler = + ext4_xattr_handler(entry->e_name_index); + + if (handler && (!handler->list || handler->list(dentry))) { + const char *prefix = handler->prefix ?: handler->name; + size_t prefix_len = strlen(prefix); + size_t size = prefix_len + entry->e_name_len + 1; + + if (buffer) { + if (size > rest) + return -ERANGE; + memcpy(buffer, prefix, prefix_len); + buffer += prefix_len; + memcpy(buffer, entry->e_name, entry->e_name_len); + buffer += entry->e_name_len; + *buffer++ = 0; + } + rest -= size; + } + } + return buffer_size - rest; /* total size */ +} + +static int +ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size) +{ + struct inode *inode = d_inode(dentry); + struct buffer_head *bh = NULL; + int error; + + ea_idebug(inode, "buffer=%p, buffer_size=%ld", + buffer, (long)buffer_size); + + if (!EXT4_I(inode)->i_file_acl) + return 0; + ea_idebug(inode, "reading block %llu", + (unsigned long long)EXT4_I(inode)->i_file_acl); + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) + return PTR_ERR(bh); + ea_bdebug(bh, "b_count=%d, refcount=%d", + atomic_read(&(bh->b_count)), le32_to_cpu(BHDR(bh)->h_refcount)); + error = ext4_xattr_check_block(inode, bh); + if (error) + goto cleanup; + ext4_xattr_block_cache_insert(EA_BLOCK_CACHE(inode), 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 = d_inode(dentry); + 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 = xattr_check_inode(inode, header, end); + if (error) + goto cleanup; + error = ext4_xattr_list_entries(dentry, IFIRST(header), + buffer, buffer_size); + +cleanup: + brelse(iloc.bh); + return error; +} + +/* + * Inode operation listxattr() + * + * d_inode(dentry)->i_rwsem: don't care + * + * 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. + */ +ssize_t +ext4_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) +{ + int ret, ret2; + + down_read(&EXT4_I(d_inode(dentry))->xattr_sem); + ret = ret2 = ext4_xattr_ibody_list(dentry, buffer, buffer_size); + if (ret < 0) + goto errout; + if (buffer) { + buffer += ret; + buffer_size -= ret; + } + ret = ext4_xattr_block_list(dentry, buffer, buffer_size); + if (ret < 0) + goto errout; + ret += ret2; +errout: + up_read(&EXT4_I(d_inode(dentry))->xattr_sem); + return ret; +} + +/* + * 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_feature_xattr(sb)) + return; + + BUFFER_TRACE(EXT4_SB(sb)->s_sbh, "get_write_access"); + if (ext4_journal_get_write_access(handle, sb, EXT4_SB(sb)->s_sbh, + EXT4_JTR_NONE) == 0) { + lock_buffer(EXT4_SB(sb)->s_sbh); + ext4_set_feature_xattr(sb); + ext4_superblock_csum_set(sb); + unlock_buffer(EXT4_SB(sb)->s_sbh); + ext4_handle_dirty_metadata(handle, NULL, EXT4_SB(sb)->s_sbh); + } +} + +int ext4_get_inode_usage(struct inode *inode, qsize_t *usage) +{ + struct ext4_iloc iloc = { .bh = NULL }; + struct buffer_head *bh = NULL; + struct ext4_inode *raw_inode; + struct ext4_xattr_ibody_header *header; + struct ext4_xattr_entry *entry; + qsize_t ea_inode_refs = 0; + void *end; + int ret; + + lockdep_assert_held_read(&EXT4_I(inode)->xattr_sem); + + if (ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { + ret = ext4_get_inode_loc(inode, &iloc); + if (ret) + goto out; + raw_inode = ext4_raw_inode(&iloc); + header = IHDR(inode, raw_inode); + end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; + ret = xattr_check_inode(inode, header, end); + if (ret) + goto out; + + for (entry = IFIRST(header); !IS_LAST_ENTRY(entry); + entry = EXT4_XATTR_NEXT(entry)) + if (entry->e_value_inum) + ea_inode_refs++; + } + + if (EXT4_I(inode)->i_file_acl) { + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) { + ret = PTR_ERR(bh); + bh = NULL; + goto out; + } + + ret = ext4_xattr_check_block(inode, bh); + if (ret) + goto out; + + for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry); + entry = EXT4_XATTR_NEXT(entry)) + if (entry->e_value_inum) + ea_inode_refs++; + } + *usage = ea_inode_refs + 1; + ret = 0; +out: + brelse(iloc.bh); + brelse(bh); + return ret; +} + +static inline size_t round_up_cluster(struct inode *inode, size_t length) +{ + struct super_block *sb = inode->i_sb; + size_t cluster_size = 1 << (EXT4_SB(sb)->s_cluster_bits + + inode->i_blkbits); + size_t mask = ~(cluster_size - 1); + + return (length + cluster_size - 1) & mask; +} + +static int ext4_xattr_inode_alloc_quota(struct inode *inode, size_t len) +{ + int err; + + err = dquot_alloc_inode(inode); + if (err) + return err; + err = dquot_alloc_space_nodirty(inode, round_up_cluster(inode, len)); + if (err) + dquot_free_inode(inode); + return err; +} + +static void ext4_xattr_inode_free_quota(struct inode *parent, + struct inode *ea_inode, + size_t len) +{ + if (ea_inode && + ext4_test_inode_state(ea_inode, EXT4_STATE_LUSTRE_EA_INODE)) + return; + dquot_free_space_nodirty(parent, round_up_cluster(parent, len)); + dquot_free_inode(parent); +} + +int __ext4_xattr_set_credits(struct super_block *sb, struct inode *inode, + struct buffer_head *block_bh, size_t value_len, + bool is_create) +{ + int credits; + int blocks; + + /* + * 1) Owner inode update + * 2) Ref count update on old xattr block + * 3) new xattr block + * 4) block bitmap update for new xattr block + * 5) group descriptor for new xattr block + * 6) block bitmap update for old xattr block + * 7) group descriptor for old block + * + * 6 & 7 can happen if we have two racing threads T_a and T_b + * which are each trying to set an xattr on inodes I_a and I_b + * which were both initially sharing an xattr block. + */ + credits = 7; + + /* Quota updates. */ + credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(sb); + + /* + * In case of inline data, we may push out the data to a block, + * so we need to reserve credits for this eventuality + */ + if (inode && ext4_has_inline_data(inode)) + credits += ext4_writepage_trans_blocks(inode) + 1; + + /* We are done if ea_inode feature is not enabled. */ + if (!ext4_has_feature_ea_inode(sb)) + return credits; + + /* New ea_inode, inode map, block bitmap, group descriptor. */ + credits += 4; + + /* Data blocks. */ + blocks = (value_len + sb->s_blocksize - 1) >> sb->s_blocksize_bits; + + /* Indirection block or one level of extent tree. */ + blocks += 1; + + /* Block bitmap and group descriptor updates for each block. */ + credits += blocks * 2; + + /* Blocks themselves. */ + credits += blocks; + + if (!is_create) { + /* Dereference ea_inode holding old xattr value. + * Old ea_inode, inode map, block bitmap, group descriptor. + */ + credits += 4; + + /* Data blocks for old ea_inode. */ + blocks = XATTR_SIZE_MAX >> sb->s_blocksize_bits; + + /* Indirection block or one level of extent tree for old + * ea_inode. + */ + blocks += 1; + + /* Block bitmap and group descriptor updates for each block. */ + credits += blocks * 2; + } + + /* We may need to clone the existing xattr block in which case we need + * to increment ref counts for existing ea_inodes referenced by it. + */ + if (block_bh) { + struct ext4_xattr_entry *entry = BFIRST(block_bh); + + for (; !IS_LAST_ENTRY(entry); entry = EXT4_XATTR_NEXT(entry)) + if (entry->e_value_inum) + /* Ref count update on ea_inode. */ + credits += 1; + } + return credits; +} + +static int ext4_xattr_inode_update_ref(handle_t *handle, struct inode *ea_inode, + int ref_change) +{ + struct ext4_iloc iloc; + s64 ref_count; + int ret; + + inode_lock(ea_inode); + + ret = ext4_reserve_inode_write(handle, ea_inode, &iloc); + if (ret) + goto out; + + ref_count = ext4_xattr_inode_get_ref(ea_inode); + ref_count += ref_change; + ext4_xattr_inode_set_ref(ea_inode, ref_count); + + if (ref_change > 0) { + WARN_ONCE(ref_count <= 0, "EA inode %lu ref_count=%lld", + ea_inode->i_ino, ref_count); + + if (ref_count == 1) { + WARN_ONCE(ea_inode->i_nlink, "EA inode %lu i_nlink=%u", + ea_inode->i_ino, ea_inode->i_nlink); + + set_nlink(ea_inode, 1); + ext4_orphan_del(handle, ea_inode); + } + } else { + WARN_ONCE(ref_count < 0, "EA inode %lu ref_count=%lld", + ea_inode->i_ino, ref_count); + + if (ref_count == 0) { + WARN_ONCE(ea_inode->i_nlink != 1, + "EA inode %lu i_nlink=%u", + ea_inode->i_ino, ea_inode->i_nlink); + + clear_nlink(ea_inode); + ext4_orphan_add(handle, ea_inode); + } + } + + ret = ext4_mark_iloc_dirty(handle, ea_inode, &iloc); + if (ret) + ext4_warning_inode(ea_inode, + "ext4_mark_iloc_dirty() failed ret=%d", ret); +out: + inode_unlock(ea_inode); + return ret; +} + +static int ext4_xattr_inode_inc_ref(handle_t *handle, struct inode *ea_inode) +{ + return ext4_xattr_inode_update_ref(handle, ea_inode, 1); +} + +static int ext4_xattr_inode_dec_ref(handle_t *handle, struct inode *ea_inode) +{ + return ext4_xattr_inode_update_ref(handle, ea_inode, -1); +} + +static int ext4_xattr_inode_inc_ref_all(handle_t *handle, struct inode *parent, + struct ext4_xattr_entry *first) +{ + struct inode *ea_inode; + struct ext4_xattr_entry *entry; + struct ext4_xattr_entry *failed_entry; + unsigned int ea_ino; + int err, saved_err; + + for (entry = first; !IS_LAST_ENTRY(entry); + entry = EXT4_XATTR_NEXT(entry)) { + if (!entry->e_value_inum) + continue; + ea_ino = le32_to_cpu(entry->e_value_inum); + err = ext4_xattr_inode_iget(parent, ea_ino, + le32_to_cpu(entry->e_hash), + &ea_inode); + if (err) + goto cleanup; + err = ext4_xattr_inode_inc_ref(handle, ea_inode); + if (err) { + ext4_warning_inode(ea_inode, "inc ref error %d", err); + iput(ea_inode); + goto cleanup; + } + iput(ea_inode); + } + return 0; + +cleanup: + saved_err = err; + failed_entry = entry; + + for (entry = first; entry != failed_entry; + entry = EXT4_XATTR_NEXT(entry)) { + if (!entry->e_value_inum) + continue; + ea_ino = le32_to_cpu(entry->e_value_inum); + err = ext4_xattr_inode_iget(parent, ea_ino, + le32_to_cpu(entry->e_hash), + &ea_inode); + if (err) { + ext4_warning(parent->i_sb, + "cleanup ea_ino %u iget error %d", ea_ino, + err); + continue; + } + err = ext4_xattr_inode_dec_ref(handle, ea_inode); + if (err) + ext4_warning_inode(ea_inode, "cleanup dec ref error %d", + err); + iput(ea_inode); + } + return saved_err; +} + +static int ext4_xattr_restart_fn(handle_t *handle, struct inode *inode, + struct buffer_head *bh, bool block_csum, bool dirty) +{ + int error; + + if (bh && dirty) { + if (block_csum) + ext4_xattr_block_csum_set(inode, bh); + error = ext4_handle_dirty_metadata(handle, NULL, bh); + if (error) { + ext4_warning(inode->i_sb, "Handle metadata (error %d)", + error); + return error; + } + } + return 0; +} + +static void +ext4_xattr_inode_dec_ref_all(handle_t *handle, struct inode *parent, + struct buffer_head *bh, + struct ext4_xattr_entry *first, bool block_csum, + struct ext4_xattr_inode_array **ea_inode_array, + int extra_credits, bool skip_quota) +{ + struct inode *ea_inode; + struct ext4_xattr_entry *entry; + bool dirty = false; + unsigned int ea_ino; + int err; + int credits; + + /* One credit for dec ref on ea_inode, one for orphan list addition, */ + credits = 2 + extra_credits; + + for (entry = first; !IS_LAST_ENTRY(entry); + entry = EXT4_XATTR_NEXT(entry)) { + if (!entry->e_value_inum) + continue; + ea_ino = le32_to_cpu(entry->e_value_inum); + err = ext4_xattr_inode_iget(parent, ea_ino, + le32_to_cpu(entry->e_hash), + &ea_inode); + if (err) + continue; + + err = ext4_expand_inode_array(ea_inode_array, ea_inode); + if (err) { + ext4_warning_inode(ea_inode, + "Expand inode array err=%d", err); + iput(ea_inode); + continue; + } + + err = ext4_journal_ensure_credits_fn(handle, credits, credits, + ext4_free_metadata_revoke_credits(parent->i_sb, 1), + ext4_xattr_restart_fn(handle, parent, bh, block_csum, + dirty)); + if (err < 0) { + ext4_warning_inode(ea_inode, "Ensure credits err=%d", + err); + continue; + } + if (err > 0) { + err = ext4_journal_get_write_access(handle, + parent->i_sb, bh, EXT4_JTR_NONE); + if (err) { + ext4_warning_inode(ea_inode, + "Re-get write access err=%d", + err); + continue; + } + } + + err = ext4_xattr_inode_dec_ref(handle, ea_inode); + if (err) { + ext4_warning_inode(ea_inode, "ea_inode dec ref err=%d", + err); + continue; + } + + if (!skip_quota) + ext4_xattr_inode_free_quota(parent, ea_inode, + le32_to_cpu(entry->e_value_size)); + + /* + * Forget about ea_inode within the same transaction that + * decrements the ref count. This avoids duplicate decrements in + * case the rest of the work spills over to subsequent + * transactions. + */ + entry->e_value_inum = 0; + entry->e_value_size = 0; + + dirty = true; + } + + if (dirty) { + /* + * Note that we are deliberately skipping csum calculation for + * the final update because we do not expect any journal + * restarts until xattr block is freed. + */ + + err = ext4_handle_dirty_metadata(handle, NULL, bh); + if (err) + ext4_warning_inode(parent, + "handle dirty metadata err=%d", err); + } +} + +/* + * 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 ext4_xattr_inode_array **ea_inode_array, + int extra_credits) +{ + struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode); + u32 hash, ref; + int error = 0; + + BUFFER_TRACE(bh, "get_write_access"); + error = ext4_journal_get_write_access(handle, inode->i_sb, bh, + EXT4_JTR_NONE); + if (error) + goto out; + +retry_ref: + lock_buffer(bh); + hash = le32_to_cpu(BHDR(bh)->h_hash); + ref = le32_to_cpu(BHDR(bh)->h_refcount); + if (ref == 1) { + ea_bdebug(bh, "refcount now=0; freeing"); + /* + * This must happen under buffer lock for + * ext4_xattr_block_set() to reliably detect freed block + */ + if (ea_block_cache) { + struct mb_cache_entry *oe; + + oe = mb_cache_entry_delete_or_get(ea_block_cache, hash, + bh->b_blocknr); + if (oe) { + unlock_buffer(bh); + mb_cache_entry_wait_unused(oe); + mb_cache_entry_put(ea_block_cache, oe); + goto retry_ref; + } + } + get_bh(bh); + unlock_buffer(bh); + + if (ext4_has_feature_ea_inode(inode->i_sb)) + ext4_xattr_inode_dec_ref_all(handle, inode, bh, + BFIRST(bh), + true /* block_csum */, + ea_inode_array, + extra_credits, + true /* skip_quota */); + ext4_free_blocks(handle, inode, bh, 0, 1, + EXT4_FREE_BLOCKS_METADATA | + EXT4_FREE_BLOCKS_FORGET); + } else { + ref--; + BHDR(bh)->h_refcount = cpu_to_le32(ref); + if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) { + struct mb_cache_entry *ce; + + if (ea_block_cache) { + ce = mb_cache_entry_get(ea_block_cache, hash, + bh->b_blocknr); + if (ce) { + set_bit(MBE_REUSABLE_B, &ce->e_flags); + mb_cache_entry_put(ea_block_cache, ce); + } + } + } + + ext4_xattr_block_csum_set(inode, bh); + /* + * Beware of this ugliness: Releasing of xattr block references + * from different inodes can race and so we have to protect + * from a race where someone else frees the block (and releases + * its journal_head) before we are done dirtying the buffer. In + * nojournal mode this race is harmless and we actually cannot + * call ext4_handle_dirty_metadata() with locked buffer as + * that function can call sync_dirty_buffer() so for that case + * we handle the dirtying after unlocking the buffer. + */ + if (ext4_handle_valid(handle)) + error = ext4_handle_dirty_metadata(handle, inode, bh); + unlock_buffer(bh); + if (!ext4_handle_valid(handle)) + error = ext4_handle_dirty_metadata(handle, inode, bh); + if (IS_SYNC(inode)) + ext4_handle_sync(handle); + dquot_free_block(inode, EXT4_C2B(EXT4_SB(inode->i_sb), 1)); + ea_bdebug(bh, "refcount now=%d; releasing", + le32_to_cpu(BHDR(bh)->h_refcount)); + } +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)) { + if (!last->e_value_inum && last->e_value_size) { + size_t offs = le16_to_cpu(last->e_value_offs); + if (offs < *min_offs) + *min_offs = offs; + } + if (total) + *total += EXT4_XATTR_LEN(last->e_name_len); + } + return (*min_offs - ((void *)last - base) - sizeof(__u32)); +} + +/* + * Write the value of the EA in an inode. + */ +static int ext4_xattr_inode_write(handle_t *handle, struct inode *ea_inode, + const void *buf, int bufsize) +{ + struct buffer_head *bh = NULL; + unsigned long block = 0; + int blocksize = ea_inode->i_sb->s_blocksize; + int max_blocks = (bufsize + blocksize - 1) >> ea_inode->i_blkbits; + int csize, wsize = 0; + int ret = 0, ret2 = 0; + int retries = 0; + +retry: + while (ret >= 0 && ret < max_blocks) { + struct ext4_map_blocks map; + map.m_lblk = block += ret; + map.m_len = max_blocks -= ret; + + ret = ext4_map_blocks(handle, ea_inode, &map, + EXT4_GET_BLOCKS_CREATE); + if (ret <= 0) { + ext4_mark_inode_dirty(handle, ea_inode); + if (ret == -ENOSPC && + ext4_should_retry_alloc(ea_inode->i_sb, &retries)) { + ret = 0; + goto retry; + } + break; + } + } + + if (ret < 0) + return ret; + + block = 0; + while (wsize < bufsize) { + brelse(bh); + csize = (bufsize - wsize) > blocksize ? blocksize : + bufsize - wsize; + bh = ext4_getblk(handle, ea_inode, block, 0); + if (IS_ERR(bh)) + return PTR_ERR(bh); + if (!bh) { + WARN_ON_ONCE(1); + EXT4_ERROR_INODE(ea_inode, + "ext4_getblk() return bh = NULL"); + return -EFSCORRUPTED; + } + ret = ext4_journal_get_write_access(handle, ea_inode->i_sb, bh, + EXT4_JTR_NONE); + if (ret) + goto out; + + memcpy(bh->b_data, buf, csize); + set_buffer_uptodate(bh); + ext4_handle_dirty_metadata(handle, ea_inode, bh); + + buf += csize; + wsize += csize; + block += 1; + } + + inode_lock(ea_inode); + i_size_write(ea_inode, wsize); + ext4_update_i_disksize(ea_inode, wsize); + inode_unlock(ea_inode); + + ret2 = ext4_mark_inode_dirty(handle, ea_inode); + if (unlikely(ret2 && !ret)) + ret = ret2; + +out: + brelse(bh); + + return ret; +} + +/* + * Create an inode to store the value of a large EA. + */ +static struct inode *ext4_xattr_inode_create(handle_t *handle, + struct inode *inode, u32 hash) +{ + struct inode *ea_inode = NULL; + uid_t owner[2] = { i_uid_read(inode), i_gid_read(inode) }; + int err; + + if (inode->i_sb->s_root == NULL) { + ext4_warning(inode->i_sb, + "refuse to create EA inode when umounting"); + WARN_ON(1); + return ERR_PTR(-EINVAL); + } + + /* + * Let the next inode be the goal, so we try and allocate the EA inode + * in the same group, or nearby one. + */ + ea_inode = ext4_new_inode(handle, inode->i_sb->s_root->d_inode, + S_IFREG | 0600, NULL, inode->i_ino + 1, owner, + EXT4_EA_INODE_FL); + if (!IS_ERR(ea_inode)) { + ea_inode->i_op = &ext4_file_inode_operations; + ea_inode->i_fop = &ext4_file_operations; + ext4_set_aops(ea_inode); + ext4_xattr_inode_set_class(ea_inode); + unlock_new_inode(ea_inode); + ext4_xattr_inode_set_ref(ea_inode, 1); + ext4_xattr_inode_set_hash(ea_inode, hash); + err = ext4_mark_inode_dirty(handle, ea_inode); + if (!err) + err = ext4_inode_attach_jinode(ea_inode); + if (err) { + if (ext4_xattr_inode_dec_ref(handle, ea_inode)) + ext4_warning_inode(ea_inode, + "cleanup dec ref error %d", err); + iput(ea_inode); + return ERR_PTR(err); + } + + /* + * Xattr inodes are shared therefore quota charging is performed + * at a higher level. + */ + dquot_free_inode(ea_inode); + dquot_drop(ea_inode); + inode_lock(ea_inode); + ea_inode->i_flags |= S_NOQUOTA; + inode_unlock(ea_inode); + } + + return ea_inode; +} + +static struct inode * +ext4_xattr_inode_cache_find(struct inode *inode, const void *value, + size_t value_len, u32 hash) +{ + struct inode *ea_inode; + struct mb_cache_entry *ce; + struct mb_cache *ea_inode_cache = EA_INODE_CACHE(inode); + void *ea_data; + + if (!ea_inode_cache) + return NULL; + + ce = mb_cache_entry_find_first(ea_inode_cache, hash); + if (!ce) + return NULL; + + WARN_ON_ONCE(ext4_handle_valid(journal_current_handle()) && + !(current->flags & PF_MEMALLOC_NOFS)); + + ea_data = kvmalloc(value_len, GFP_KERNEL); + if (!ea_data) { + mb_cache_entry_put(ea_inode_cache, ce); + return NULL; + } + + while (ce) { + ea_inode = ext4_iget(inode->i_sb, ce->e_value, + EXT4_IGET_EA_INODE); + if (IS_ERR(ea_inode)) + goto next_entry; + ext4_xattr_inode_set_class(ea_inode); + if (i_size_read(ea_inode) == value_len && + !ext4_xattr_inode_read(ea_inode, ea_data, value_len) && + !ext4_xattr_inode_verify_hashes(ea_inode, NULL, ea_data, + value_len) && + !memcmp(value, ea_data, value_len)) { + mb_cache_entry_touch(ea_inode_cache, ce); + mb_cache_entry_put(ea_inode_cache, ce); + kvfree(ea_data); + return ea_inode; + } + iput(ea_inode); + next_entry: + ce = mb_cache_entry_find_next(ea_inode_cache, ce); + } + kvfree(ea_data); + return NULL; +} + +/* + * Add value of the EA in an inode. + */ +static int ext4_xattr_inode_lookup_create(handle_t *handle, struct inode *inode, + const void *value, size_t value_len, + struct inode **ret_inode) +{ + struct inode *ea_inode; + u32 hash; + int err; + + hash = ext4_xattr_inode_hash(EXT4_SB(inode->i_sb), value, value_len); + ea_inode = ext4_xattr_inode_cache_find(inode, value, value_len, hash); + if (ea_inode) { + err = ext4_xattr_inode_inc_ref(handle, ea_inode); + if (err) { + iput(ea_inode); + return err; + } + + *ret_inode = ea_inode; + return 0; + } + + /* Create an inode for the EA value */ + ea_inode = ext4_xattr_inode_create(handle, inode, hash); + if (IS_ERR(ea_inode)) + return PTR_ERR(ea_inode); + + err = ext4_xattr_inode_write(handle, ea_inode, value, value_len); + if (err) { + ext4_xattr_inode_dec_ref(handle, ea_inode); + iput(ea_inode); + return err; + } + + if (EA_INODE_CACHE(inode)) + mb_cache_entry_create(EA_INODE_CACHE(inode), GFP_NOFS, hash, + ea_inode->i_ino, true /* reusable */); + + *ret_inode = ea_inode; + return 0; +} + +/* + * Reserve min(block_size/8, 1024) bytes for xattr entries/names if ea_inode + * feature is enabled. + */ +#define EXT4_XATTR_BLOCK_RESERVE(inode) min(i_blocksize(inode)/8, 1024U) + +static int ext4_xattr_set_entry(struct ext4_xattr_info *i, + struct ext4_xattr_search *s, + handle_t *handle, struct inode *inode, + bool is_block) +{ + struct ext4_xattr_entry *last, *next; + struct ext4_xattr_entry *here = s->here; + size_t min_offs = s->end - s->base, name_len = strlen(i->name); + int in_inode = i->in_inode; + struct inode *old_ea_inode = NULL; + struct inode *new_ea_inode = NULL; + size_t old_size, new_size; + int ret; + + /* Space used by old and new values. */ + old_size = (!s->not_found && !here->e_value_inum) ? + EXT4_XATTR_SIZE(le32_to_cpu(here->e_value_size)) : 0; + new_size = (i->value && !in_inode) ? EXT4_XATTR_SIZE(i->value_len) : 0; + + /* + * Optimization for the simple case when old and new values have the + * same padded sizes. Not applicable if external inodes are involved. + */ + if (new_size && new_size == old_size) { + size_t offs = le16_to_cpu(here->e_value_offs); + void *val = s->base + offs; + + here->e_value_size = cpu_to_le32(i->value_len); + if (i->value == EXT4_ZERO_XATTR_VALUE) { + memset(val, 0, new_size); + } else { + memcpy(val, i->value, i->value_len); + /* Clear padding bytes. */ + memset(val + i->value_len, 0, new_size - i->value_len); + } + goto update_hash; + } + + /* Compute min_offs and last. */ + last = s->first; + for (; !IS_LAST_ENTRY(last); last = next) { + next = EXT4_XATTR_NEXT(last); + if ((void *)next >= s->end) { + EXT4_ERROR_INODE(inode, "corrupted xattr entries"); + ret = -EFSCORRUPTED; + goto out; + } + if (!last->e_value_inum && last->e_value_size) { + size_t offs = le16_to_cpu(last->e_value_offs); + if (offs < min_offs) + min_offs = offs; + } + } + + /* Check whether we have enough space. */ + if (i->value) { + size_t free; + + free = min_offs - ((void *)last - s->base) - sizeof(__u32); + if (!s->not_found) + free += EXT4_XATTR_LEN(name_len) + old_size; + + if (free < EXT4_XATTR_LEN(name_len) + new_size) { + ret = -ENOSPC; + goto out; + } + + /* + * If storing the value in an external inode is an option, + * reserve space for xattr entries/names in the external + * attribute block so that a long value does not occupy the + * whole space and prevent further entries being added. + */ + if (ext4_has_feature_ea_inode(inode->i_sb) && + new_size && is_block && + (min_offs + old_size - new_size) < + EXT4_XATTR_BLOCK_RESERVE(inode)) { + ret = -ENOSPC; + goto out; + } + } + + /* + * Getting access to old and new ea inodes is subject to failures. + * Finish that work before doing any modifications to the xattr data. + */ + if (!s->not_found && here->e_value_inum) { + ret = ext4_xattr_inode_iget(inode, + le32_to_cpu(here->e_value_inum), + le32_to_cpu(here->e_hash), + &old_ea_inode); + if (ret) { + old_ea_inode = NULL; + goto out; + } + } + if (i->value && in_inode) { + WARN_ON_ONCE(!i->value_len); + + ret = ext4_xattr_inode_alloc_quota(inode, i->value_len); + if (ret) + goto out; + + ret = ext4_xattr_inode_lookup_create(handle, inode, i->value, + i->value_len, + &new_ea_inode); + if (ret) { + new_ea_inode = NULL; + ext4_xattr_inode_free_quota(inode, NULL, i->value_len); + goto out; + } + } + + if (old_ea_inode) { + /* We are ready to release ref count on the old_ea_inode. */ + ret = ext4_xattr_inode_dec_ref(handle, old_ea_inode); + if (ret) { + /* Release newly required ref count on new_ea_inode. */ + if (new_ea_inode) { + int err; + + err = ext4_xattr_inode_dec_ref(handle, + new_ea_inode); + if (err) + ext4_warning_inode(new_ea_inode, + "dec ref new_ea_inode err=%d", + err); + ext4_xattr_inode_free_quota(inode, new_ea_inode, + i->value_len); + } + goto out; + } + + ext4_xattr_inode_free_quota(inode, old_ea_inode, + le32_to_cpu(here->e_value_size)); + } + + /* No failures allowed past this point. */ + + if (!s->not_found && here->e_value_size && !here->e_value_inum) { + /* Remove the old value. */ + void *first_val = s->base + min_offs; + size_t offs = le16_to_cpu(here->e_value_offs); + void *val = s->base + offs; + + memmove(first_val + old_size, first_val, val - first_val); + memset(first_val, 0, old_size); + min_offs += old_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_inum && + last->e_value_size && o < offs) + last->e_value_offs = cpu_to_le16(o + old_size); + last = EXT4_XATTR_NEXT(last); + } + } + + if (!i->value) { + /* Remove old name. */ + size_t size = EXT4_XATTR_LEN(name_len); + + last = ENTRY((void *)last - size); + memmove(here, (void *)here + size, + (void *)last - (void *)here + sizeof(__u32)); + memset(last, 0, size); + + /* + * Update i_inline_off - moved ibody region might contain + * system.data attribute. Handling a failure here won't + * cause other complications for setting an xattr. + */ + if (!is_block && ext4_has_inline_data(inode)) { + ret = ext4_find_inline_data_nolock(inode); + if (ret) { + ext4_warning_inode(inode, + "unable to update i_inline_off"); + goto out; + } + } + } else if (s->not_found) { + /* Insert new name. */ + size_t size = EXT4_XATTR_LEN(name_len); + size_t rest = (void *)last - (void *)here + sizeof(__u32); + + memmove((void *)here + size, here, rest); + memset(here, 0, size); + here->e_name_index = i->name_index; + here->e_name_len = name_len; + memcpy(here->e_name, i->name, name_len); + } else { + /* This is an update, reset value info. */ + here->e_value_inum = 0; + here->e_value_offs = 0; + here->e_value_size = 0; + } + + if (i->value) { + /* Insert new value. */ + if (in_inode) { + here->e_value_inum = cpu_to_le32(new_ea_inode->i_ino); + } else if (i->value_len) { + void *val = s->base + min_offs - new_size; + + here->e_value_offs = cpu_to_le16(min_offs - new_size); + if (i->value == EXT4_ZERO_XATTR_VALUE) { + memset(val, 0, new_size); + } else { + memcpy(val, i->value, i->value_len); + /* Clear padding bytes. */ + memset(val + i->value_len, 0, + new_size - i->value_len); + } + } + here->e_value_size = cpu_to_le32(i->value_len); + } + +update_hash: + if (i->value) { + __le32 hash = 0; + + /* Entry hash calculation. */ + if (in_inode) { + __le32 crc32c_hash; + + /* + * Feed crc32c hash instead of the raw value for entry + * hash calculation. This is to avoid walking + * potentially long value buffer again. + */ + crc32c_hash = cpu_to_le32( + ext4_xattr_inode_get_hash(new_ea_inode)); + hash = ext4_xattr_hash_entry(here->e_name, + here->e_name_len, + &crc32c_hash, 1); + } else if (is_block) { + __le32 *value = s->base + le16_to_cpu( + here->e_value_offs); + + hash = ext4_xattr_hash_entry(here->e_name, + here->e_name_len, value, + new_size >> 2); + } + here->e_hash = hash; + } + + if (is_block) + ext4_xattr_rehash((struct ext4_xattr_header *)s->base); + + ret = 0; +out: + iput(old_ea_inode); + iput(new_ea_inode); + return ret; +} + +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 = ext4_sb_bread(sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bs->bh)) { + error = PTR_ERR(bs->bh); + bs->bh = NULL; + return error; + } + ea_bdebug(bs->bh, "b_count=%d, refcount=%d", + atomic_read(&(bs->bh->b_count)), + le32_to_cpu(BHDR(bs->bh)->h_refcount)); + error = ext4_xattr_check_block(inode, bs->bh); + if (error) + return error; + /* 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 = xattr_find_entry(inode, &bs->s.here, bs->s.end, + i->name_index, i->name, 1); + if (error && error != -ENODATA) + return error; + bs->s.not_found = error; + } + return 0; +} + +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_copy = bs->s; + struct ext4_xattr_search *s = &s_copy; + struct mb_cache_entry *ce = NULL; + int error = 0; + struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode); + struct inode *ea_inode = NULL, *tmp_inode; + size_t old_ea_inode_quota = 0; + unsigned int ea_ino; + + +#define header(x) ((struct ext4_xattr_header *)(x)) + + if (s->base) { + int offset = (char *)s->here - bs->bh->b_data; + + BUFFER_TRACE(bs->bh, "get_write_access"); + error = ext4_journal_get_write_access(handle, sb, bs->bh, + EXT4_JTR_NONE); + if (error) + goto cleanup; + lock_buffer(bs->bh); + + if (header(s->base)->h_refcount == cpu_to_le32(1)) { + __u32 hash = le32_to_cpu(BHDR(bs->bh)->h_hash); + + /* + * This must happen under buffer lock for + * ext4_xattr_block_set() to reliably detect modified + * block + */ + if (ea_block_cache) { + struct mb_cache_entry *oe; + + oe = mb_cache_entry_delete_or_get(ea_block_cache, + hash, bs->bh->b_blocknr); + if (oe) { + /* + * Xattr block is getting reused. Leave + * it alone. + */ + mb_cache_entry_put(ea_block_cache, oe); + goto clone_block; + } + } + ea_bdebug(bs->bh, "modifying in-place"); + error = ext4_xattr_set_entry(i, s, handle, inode, + true /* is_block */); + ext4_xattr_block_csum_set(inode, bs->bh); + unlock_buffer(bs->bh); + if (error == -EFSCORRUPTED) + goto bad_block; + if (!error) + error = ext4_handle_dirty_metadata(handle, + inode, + bs->bh); + if (error) + goto cleanup; + goto inserted; + } +clone_block: + unlock_buffer(bs->bh); + ea_bdebug(bs->bh, "cloning"); + s->base = kmemdup(BHDR(bs->bh), bs->bh->b_size, GFP_NOFS); + error = -ENOMEM; + if (s->base == NULL) + goto cleanup; + 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; + + /* + * If existing entry points to an xattr inode, we need + * to prevent ext4_xattr_set_entry() from decrementing + * ref count on it because the reference belongs to the + * original block. In this case, make the entry look + * like it has an empty value. + */ + if (!s->not_found && s->here->e_value_inum) { + ea_ino = le32_to_cpu(s->here->e_value_inum); + error = ext4_xattr_inode_iget(inode, ea_ino, + le32_to_cpu(s->here->e_hash), + &tmp_inode); + if (error) + goto cleanup; + + if (!ext4_test_inode_state(tmp_inode, + EXT4_STATE_LUSTRE_EA_INODE)) { + /* + * Defer quota free call for previous + * inode until success is guaranteed. + */ + old_ea_inode_quota = le32_to_cpu( + s->here->e_value_size); + } + iput(tmp_inode); + + s->here->e_value_inum = 0; + s->here->e_value_size = 0; + } + } else { + /* Allocate a buffer where we construct the new block. */ + s->base = kzalloc(sb->s_blocksize, GFP_NOFS); + 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, handle, inode, true /* is_block */); + if (error == -EFSCORRUPTED) + goto bad_block; + if (error) + goto cleanup; + + if (i->value && s->here->e_value_inum) { + /* + * A ref count on ea_inode has been taken as part of the call to + * ext4_xattr_set_entry() above. We would like to drop this + * extra ref but we have to wait until the xattr block is + * initialized and has its own ref count on the ea_inode. + */ + ea_ino = le32_to_cpu(s->here->e_value_inum); + error = ext4_xattr_inode_iget(inode, ea_ino, + le32_to_cpu(s->here->e_hash), + &ea_inode); + if (error) { + ea_inode = NULL; + goto cleanup; + } + } + +inserted: + if (!IS_LAST_ENTRY(s->first)) { + new_bh = ext4_xattr_block_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 { + u32 ref; + +#ifdef EXT4_XATTR_DEBUG + WARN_ON_ONCE(dquot_initialize_needed(inode)); +#endif + /* The old block is released after updating + the inode. */ + error = dquot_alloc_block(inode, + EXT4_C2B(EXT4_SB(sb), 1)); + if (error) + goto cleanup; + BUFFER_TRACE(new_bh, "get_write_access"); + error = ext4_journal_get_write_access( + handle, sb, new_bh, + EXT4_JTR_NONE); + if (error) + goto cleanup_dquot; + lock_buffer(new_bh); + /* + * We have to be careful about races with + * adding references to xattr block. Once we + * hold buffer lock xattr block's state is + * stable so we can check the additional + * reference fits. + */ + ref = le32_to_cpu(BHDR(new_bh)->h_refcount) + 1; + if (ref > EXT4_XATTR_REFCOUNT_MAX) { + /* + * Undo everything and check mbcache + * again. + */ + unlock_buffer(new_bh); + dquot_free_block(inode, + EXT4_C2B(EXT4_SB(sb), + 1)); + brelse(new_bh); + mb_cache_entry_put(ea_block_cache, ce); + ce = NULL; + new_bh = NULL; + goto inserted; + } + BHDR(new_bh)->h_refcount = cpu_to_le32(ref); + if (ref == EXT4_XATTR_REFCOUNT_MAX) + clear_bit(MBE_REUSABLE_B, &ce->e_flags); + ea_bdebug(new_bh, "reusing; refcount now=%d", + ref); + ext4_xattr_block_csum_set(inode, new_bh); + unlock_buffer(new_bh); + error = ext4_handle_dirty_metadata(handle, + inode, + new_bh); + if (error) + goto cleanup_dquot; + } + mb_cache_entry_touch(ea_block_cache, ce); + mb_cache_entry_put(ea_block_cache, 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"); + ext4_xattr_block_cache_insert(ea_block_cache, bs->bh); + new_bh = bs->bh; + get_bh(new_bh); + } else { + /* We need to allocate a new block */ + ext4_fsblk_t goal, block; + +#ifdef EXT4_XATTR_DEBUG + WARN_ON_ONCE(dquot_initialize_needed(inode)); +#endif + goal = ext4_group_first_block_no(sb, + EXT4_I(inode)->i_block_group); + block = ext4_new_meta_blocks(handle, inode, goal, 0, + NULL, &error); + if (error) + goto cleanup; + + ea_idebug(inode, "creating block %llu", + (unsigned long long)block); + + new_bh = sb_getblk(sb, block); + if (unlikely(!new_bh)) { + error = -ENOMEM; +getblk_failed: + ext4_free_blocks(handle, inode, NULL, block, 1, + EXT4_FREE_BLOCKS_METADATA); + goto cleanup; + } + error = ext4_xattr_inode_inc_ref_all(handle, inode, + ENTRY(header(s->base)+1)); + if (error) + goto getblk_failed; + if (ea_inode) { + /* Drop the extra ref on ea_inode. */ + error = ext4_xattr_inode_dec_ref(handle, + ea_inode); + if (error) + ext4_warning_inode(ea_inode, + "dec ref error=%d", + error); + iput(ea_inode); + ea_inode = NULL; + } + + lock_buffer(new_bh); + error = ext4_journal_get_create_access(handle, sb, + new_bh, EXT4_JTR_NONE); + if (error) { + unlock_buffer(new_bh); + error = -EIO; + goto getblk_failed; + } + memcpy(new_bh->b_data, s->base, new_bh->b_size); + ext4_xattr_block_csum_set(inode, new_bh); + set_buffer_uptodate(new_bh); + unlock_buffer(new_bh); + ext4_xattr_block_cache_insert(ea_block_cache, new_bh); + error = ext4_handle_dirty_metadata(handle, inode, + new_bh); + if (error) + goto cleanup; + } + } + + if (old_ea_inode_quota) + ext4_xattr_inode_free_quota(inode, NULL, old_ea_inode_quota); + + /* 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) { + struct ext4_xattr_inode_array *ea_inode_array = NULL; + + ext4_xattr_release_block(handle, inode, bs->bh, + &ea_inode_array, + 0 /* extra_credits */); + ext4_xattr_inode_array_free(ea_inode_array); + } + error = 0; + +cleanup: + if (ea_inode) { + int error2; + + error2 = ext4_xattr_inode_dec_ref(handle, ea_inode); + if (error2) + ext4_warning_inode(ea_inode, "dec ref error=%d", + error2); + + /* If there was an error, revert the quota charge. */ + if (error) + ext4_xattr_inode_free_quota(inode, ea_inode, + i_size_read(ea_inode)); + iput(ea_inode); + } + if (ce) + mb_cache_entry_put(ea_block_cache, ce); + brelse(new_bh); + if (!(bs->bh && s->base == bs->bh->b_data)) + kfree(s->base); + + return error; + +cleanup_dquot: + dquot_free_block(inode, EXT4_C2B(EXT4_SB(sb), 1)); + goto cleanup; + +bad_block: + EXT4_ERROR_INODE(inode, "bad block %llu", + EXT4_I(inode)->i_file_acl); + goto cleanup; + +#undef header +} + +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_INODE_HAS_XATTR_SPACE(inode)) + 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 = xattr_check_inode(inode, header, is->s.end); + if (error) + return error; + /* Find the named attribute. */ + error = xattr_find_entry(inode, &is->s.here, is->s.end, + i->name_index, i->name, 0); + if (error && error != -ENODATA) + return error; + is->s.not_found = error; + } + return 0; +} + +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_INODE_HAS_XATTR_SPACE(inode)) + return -ENOSPC; + + error = ext4_xattr_set_entry(i, s, handle, inode, false /* is_block */); + 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; +} + +static int ext4_xattr_value_same(struct ext4_xattr_search *s, + struct ext4_xattr_info *i) +{ + void *value; + + /* When e_value_inum is set the value is stored externally. */ + if (s->here->e_value_inum) + return 0; + if (le32_to_cpu(s->here->e_value_size) != i->value_len) + return 0; + value = ((void *)s->base) + le16_to_cpu(s->here->e_value_offs); + return !memcmp(value, i->value, i->value_len); +} + +static struct buffer_head *ext4_xattr_get_block(struct inode *inode) +{ + struct buffer_head *bh; + int error; + + if (!EXT4_I(inode)->i_file_acl) + return NULL; + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) + return bh; + error = ext4_xattr_check_block(inode, bh); + if (error) { + brelse(bh); + return ERR_PTR(error); + } + return bh; +} + +/* + * ext4_xattr_set_handle() + * + * Create, replace or remove an extended attribute for this inode. Value + * 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, + .in_inode = 0, + }; + struct ext4_xattr_ibody_find is = { + .s = { .not_found = -ENODATA, }, + }; + struct ext4_xattr_block_find bs = { + .s = { .not_found = -ENODATA, }, + }; + int no_expand; + int error; + + if (!name) + return -EINVAL; + if (strlen(name) > 255) + return -ERANGE; + + ext4_write_lock_xattr(inode, &no_expand); + + /* Check journal credits under write lock. */ + if (ext4_handle_valid(handle)) { + struct buffer_head *bh; + int credits; + + bh = ext4_xattr_get_block(inode); + if (IS_ERR(bh)) { + error = PTR_ERR(bh); + goto cleanup; + } + + credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh, + value_len, + flags & XATTR_CREATE); + brelse(bh); + + if (jbd2_handle_buffer_credits(handle) < credits) { + error = -ENOSPC; + goto cleanup; + } + WARN_ON_ONCE(!(current->flags & PF_MEMALLOC_NOFS)); + } + + error = ext4_reserve_inode_write(handle, inode, &is.iloc); + 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 = 0; + /* Xattr value did not change? Save us some work and bail out */ + if (!is.s.not_found && ext4_xattr_value_same(&is.s, &i)) + goto cleanup; + if (!bs.s.not_found && ext4_xattr_value_same(&bs.s, &i)) + goto cleanup; + + if (ext4_has_feature_ea_inode(inode->i_sb) && + (EXT4_XATTR_SIZE(i.value_len) > + EXT4_XATTR_MIN_LARGE_EA_SIZE(inode->i_sb->s_blocksize))) + i.in_inode = 1; +retry_inode: + 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) { + brelse(bs.bh); + bs.bh = NULL; + error = ext4_xattr_block_find(inode, &i, &bs); + if (error) + goto cleanup; + } + error = ext4_xattr_block_set(handle, inode, &i, &bs); + if (!error && !is.s.not_found) { + i.value = NULL; + error = ext4_xattr_ibody_set(handle, inode, &i, + &is); + } else if (error == -ENOSPC) { + /* + * Xattr does not fit in the block, store at + * external inode if possible. + */ + if (ext4_has_feature_ea_inode(inode->i_sb) && + i.value_len && !i.in_inode) { + i.in_inode = 1; + goto retry_inode; + } + } + } + } + if (!error) { + ext4_xattr_update_super_block(handle, inode->i_sb); + inode->i_ctime = current_time(inode); + inode_inc_iversion(inode); + if (!value) + no_expand = 0; + 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); + } + ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle); + +cleanup: + brelse(is.iloc.bh); + brelse(bs.bh); + ext4_write_unlock_xattr(inode, &no_expand); + return error; +} + +int ext4_xattr_set_credits(struct inode *inode, size_t value_len, + bool is_create, int *credits) +{ + struct buffer_head *bh; + int err; + + *credits = 0; + + if (!EXT4_SB(inode->i_sb)->s_journal) + return 0; + + down_read(&EXT4_I(inode)->xattr_sem); + + bh = ext4_xattr_get_block(inode); + if (IS_ERR(bh)) { + err = PTR_ERR(bh); + } else { + *credits = __ext4_xattr_set_credits(inode->i_sb, inode, bh, + value_len, is_create); + brelse(bh); + err = 0; + } + + up_read(&EXT4_I(inode)->xattr_sem); + return err; +} + +/* + * 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; + struct super_block *sb = inode->i_sb; + int error, retries = 0; + int credits; + + error = dquot_initialize(inode); + if (error) + return error; + +retry: + error = ext4_xattr_set_credits(inode, value_len, flags & XATTR_CREATE, + &credits); + if (error) + return error; + + handle = ext4_journal_start(inode, EXT4_HT_XATTR, credits); + 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(sb, &retries)) + goto retry; + if (error == 0) + error = error2; + } + ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, NULL); + + 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) +{ + struct ext4_xattr_entry *last = entry; + int new_offs; + + /* We always shift xattr headers further thus offsets get lower */ + BUG_ON(value_offs_shift > 0); + + /* Adjust the value offsets of the entries */ + for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { + if (!last->e_value_inum && last->e_value_size) { + new_offs = le16_to_cpu(last->e_value_offs) + + value_offs_shift; + last->e_value_offs = cpu_to_le16(new_offs); + } + } + /* Shift the entries by n bytes */ + memmove(to, from, n); +} + +/* + * Move xattr pointed to by 'entry' from inode into external xattr block + */ +static int ext4_xattr_move_to_block(handle_t *handle, struct inode *inode, + struct ext4_inode *raw_inode, + struct ext4_xattr_entry *entry) +{ + struct ext4_xattr_ibody_find *is = NULL; + struct ext4_xattr_block_find *bs = NULL; + char *buffer = NULL, *b_entry_name = NULL; + size_t value_size = le32_to_cpu(entry->e_value_size); + struct ext4_xattr_info i = { + .value = NULL, + .value_len = 0, + .name_index = entry->e_name_index, + .in_inode = !!entry->e_value_inum, + }; + struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode); + int needs_kvfree = 0; + int error; + + is = kzalloc(sizeof(struct ext4_xattr_ibody_find), GFP_NOFS); + bs = kzalloc(sizeof(struct ext4_xattr_block_find), GFP_NOFS); + b_entry_name = kmalloc(entry->e_name_len + 1, GFP_NOFS); + if (!is || !bs || !b_entry_name) { + error = -ENOMEM; + goto out; + } + + is->s.not_found = -ENODATA; + bs->s.not_found = -ENODATA; + is->iloc.bh = NULL; + bs->bh = NULL; + + /* Save the entry name and the entry value */ + if (entry->e_value_inum) { + buffer = kvmalloc(value_size, GFP_NOFS); + if (!buffer) { + error = -ENOMEM; + goto out; + } + needs_kvfree = 1; + error = ext4_xattr_inode_get(inode, entry, buffer, value_size); + if (error) + goto out; + } else { + size_t value_offs = le16_to_cpu(entry->e_value_offs); + buffer = (void *)IFIRST(header) + value_offs; + } + + 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 out; + + error = ext4_xattr_ibody_find(inode, &i, is); + if (error) + goto out; + + i.value = buffer; + i.value_len = value_size; + error = ext4_xattr_block_find(inode, &i, bs); + if (error) + goto out; + + /* Move ea entry from the inode into the block */ + error = ext4_xattr_block_set(handle, inode, &i, bs); + if (error) + goto out; + + /* Remove the chosen entry from the inode */ + i.value = NULL; + i.value_len = 0; + error = ext4_xattr_ibody_set(handle, inode, &i, is); + +out: + kfree(b_entry_name); + if (needs_kvfree && buffer) + kvfree(buffer); + if (is) + brelse(is->iloc.bh); + if (bs) + brelse(bs->bh); + kfree(is); + kfree(bs); + + return error; +} + +static int ext4_xattr_make_inode_space(handle_t *handle, struct inode *inode, + struct ext4_inode *raw_inode, + int isize_diff, size_t ifree, + size_t bfree, int *total_ino) +{ + struct ext4_xattr_ibody_header *header = IHDR(inode, raw_inode); + struct ext4_xattr_entry *small_entry; + struct ext4_xattr_entry *entry; + struct ext4_xattr_entry *last; + unsigned int entry_size; /* EA entry size */ + unsigned int total_size; /* EA entry size + value size */ + unsigned int min_total_size; + int error; + + while (isize_diff > ifree) { + entry = NULL; + small_entry = NULL; + min_total_size = ~0U; + last = IFIRST(header); + /* Find the entry best suited to be pushed into EA block */ + for (; !IS_LAST_ENTRY(last); last = EXT4_XATTR_NEXT(last)) { + /* never move system.data out of the inode */ + if ((last->e_name_len == 4) && + (last->e_name_index == EXT4_XATTR_INDEX_SYSTEM) && + !memcmp(last->e_name, "data", 4)) + continue; + total_size = EXT4_XATTR_LEN(last->e_name_len); + if (!last->e_value_inum) + total_size += EXT4_XATTR_SIZE( + le32_to_cpu(last->e_value_size)); + if (total_size <= bfree && + total_size < min_total_size) { + if (total_size + ifree < isize_diff) { + small_entry = last; + } else { + entry = last; + min_total_size = total_size; + } + } + } + + if (entry == NULL) { + if (small_entry == NULL) + return -ENOSPC; + entry = small_entry; + } + + entry_size = EXT4_XATTR_LEN(entry->e_name_len); + total_size = entry_size; + if (!entry->e_value_inum) + total_size += EXT4_XATTR_SIZE( + le32_to_cpu(entry->e_value_size)); + error = ext4_xattr_move_to_block(handle, inode, raw_inode, + entry); + if (error) + return error; + + *total_ino -= entry_size; + ifree += total_size; + bfree -= total_size; + } + + return 0; +} + +/* + * 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_sb_info *sbi = EXT4_SB(inode->i_sb); + static unsigned int mnt_count; + size_t min_offs; + size_t ifree, bfree; + int total_ino; + void *base, *end; + int error = 0, tried_min_extra_isize = 0; + int s_min_extra_isize = le16_to_cpu(sbi->s_es->s_min_extra_isize); + int isize_diff; /* How much do we need to grow i_extra_isize */ + +retry: + isize_diff = new_extra_isize - EXT4_I(inode)->i_extra_isize; + if (EXT4_I(inode)->i_extra_isize >= new_extra_isize) + return 0; + + header = IHDR(inode, raw_inode); + + /* + * Check if enough free space is available in the inode to shift the + * entries ahead by new_extra_isize. + */ + + base = IFIRST(header); + end = (void *)raw_inode + EXT4_SB(inode->i_sb)->s_inode_size; + min_offs = end - base; + total_ino = sizeof(struct ext4_xattr_ibody_header) + sizeof(u32); + + error = xattr_check_inode(inode, header, end); + if (error) + goto cleanup; + + ifree = ext4_xattr_free_space(base, &min_offs, base, &total_ino); + if (ifree >= isize_diff) + goto shift; + + /* + * 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) { + struct buffer_head *bh; + + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) { + error = PTR_ERR(bh); + goto cleanup; + } + error = ext4_xattr_check_block(inode, bh); + if (error) { + brelse(bh); + goto cleanup; + } + base = BHDR(bh); + end = bh->b_data + bh->b_size; + min_offs = end - base; + bfree = ext4_xattr_free_space(BFIRST(bh), &min_offs, base, + NULL); + brelse(bh); + if (bfree + ifree < isize_diff) { + if (!tried_min_extra_isize && s_min_extra_isize) { + tried_min_extra_isize++; + new_extra_isize = s_min_extra_isize; + goto retry; + } + error = -ENOSPC; + goto cleanup; + } + } else { + bfree = inode->i_sb->s_blocksize; + } + + error = ext4_xattr_make_inode_space(handle, inode, raw_inode, + isize_diff, ifree, bfree, + &total_ino); + if (error) { + if (error == -ENOSPC && !tried_min_extra_isize && + s_min_extra_isize) { + tried_min_extra_isize++; + new_extra_isize = s_min_extra_isize; + goto retry; + } + goto cleanup; + } +shift: + /* Adjust the offsets and shift the remaining entries ahead */ + ext4_xattr_shift_entries(IFIRST(header), EXT4_I(inode)->i_extra_isize + - new_extra_isize, (void *)raw_inode + + EXT4_GOOD_OLD_INODE_SIZE + new_extra_isize, + (void *)header, total_ino); + EXT4_I(inode)->i_extra_isize = new_extra_isize; + + if (ext4_has_inline_data(inode)) + error = ext4_find_inline_data_nolock(inode); + +cleanup: + if (error && (mnt_count != le16_to_cpu(sbi->s_es->s_mnt_count))) { + ext4_warning(inode->i_sb, "Unable to expand inode %lu. Delete some EAs or run e2fsck.", + inode->i_ino); + mnt_count = le16_to_cpu(sbi->s_es->s_mnt_count); + } + return error; +} + +#define EIA_INCR 16 /* must be 2^n */ +#define EIA_MASK (EIA_INCR - 1) + +/* Add the large xattr @inode into @ea_inode_array for deferred iput(). + * If @ea_inode_array is new or full it will be grown and the old + * contents copied over. + */ +static int +ext4_expand_inode_array(struct ext4_xattr_inode_array **ea_inode_array, + struct inode *inode) +{ + if (*ea_inode_array == NULL) { + /* + * Start with 15 inodes, so it fits into a power-of-two size. + * If *ea_inode_array is NULL, this is essentially offsetof() + */ + (*ea_inode_array) = + kmalloc(offsetof(struct ext4_xattr_inode_array, + inodes[EIA_MASK]), + GFP_NOFS); + if (*ea_inode_array == NULL) + return -ENOMEM; + (*ea_inode_array)->count = 0; + } else if (((*ea_inode_array)->count & EIA_MASK) == EIA_MASK) { + /* expand the array once all 15 + n * 16 slots are full */ + struct ext4_xattr_inode_array *new_array = NULL; + int count = (*ea_inode_array)->count; + + /* if new_array is NULL, this is essentially offsetof() */ + new_array = kmalloc( + offsetof(struct ext4_xattr_inode_array, + inodes[count + EIA_INCR]), + GFP_NOFS); + if (new_array == NULL) + return -ENOMEM; + memcpy(new_array, *ea_inode_array, + offsetof(struct ext4_xattr_inode_array, inodes[count])); + kfree(*ea_inode_array); + *ea_inode_array = new_array; + } + (*ea_inode_array)->inodes[(*ea_inode_array)->count++] = inode; + return 0; +} + +/* + * ext4_xattr_delete_inode() + * + * Free extended attribute resources associated with this inode. Traverse + * all entries and decrement reference on any xattr inodes associated with this + * inode. This is called immediately before an inode is freed. We have exclusive + * access to the inode. If an orphan inode is deleted it will also release its + * references on xattr block and xattr inodes. + */ +int ext4_xattr_delete_inode(handle_t *handle, struct inode *inode, + struct ext4_xattr_inode_array **ea_inode_array, + int extra_credits) +{ + struct buffer_head *bh = NULL; + struct ext4_xattr_ibody_header *header; + struct ext4_iloc iloc = { .bh = NULL }; + struct ext4_xattr_entry *entry; + struct inode *ea_inode; + int error; + + error = ext4_journal_ensure_credits(handle, extra_credits, + ext4_free_metadata_revoke_credits(inode->i_sb, 1)); + if (error < 0) { + EXT4_ERROR_INODE(inode, "ensure credits (error %d)", error); + goto cleanup; + } + + if (ext4_has_feature_ea_inode(inode->i_sb) && + ext4_test_inode_state(inode, EXT4_STATE_XATTR)) { + + error = ext4_get_inode_loc(inode, &iloc); + if (error) { + EXT4_ERROR_INODE(inode, "inode loc (error %d)", error); + goto cleanup; + } + + error = ext4_journal_get_write_access(handle, inode->i_sb, + iloc.bh, EXT4_JTR_NONE); + if (error) { + EXT4_ERROR_INODE(inode, "write access (error %d)", + error); + goto cleanup; + } + + header = IHDR(inode, ext4_raw_inode(&iloc)); + if (header->h_magic == cpu_to_le32(EXT4_XATTR_MAGIC)) + ext4_xattr_inode_dec_ref_all(handle, inode, iloc.bh, + IFIRST(header), + false /* block_csum */, + ea_inode_array, + extra_credits, + false /* skip_quota */); + } + + if (EXT4_I(inode)->i_file_acl) { + bh = ext4_sb_bread(inode->i_sb, EXT4_I(inode)->i_file_acl, REQ_PRIO); + if (IS_ERR(bh)) { + error = PTR_ERR(bh); + if (error == -EIO) { + EXT4_ERROR_INODE_ERR(inode, EIO, + "block %llu read error", + EXT4_I(inode)->i_file_acl); + } + bh = NULL; + goto cleanup; + } + error = ext4_xattr_check_block(inode, bh); + if (error) + goto cleanup; + + if (ext4_has_feature_ea_inode(inode->i_sb)) { + for (entry = BFIRST(bh); !IS_LAST_ENTRY(entry); + entry = EXT4_XATTR_NEXT(entry)) { + if (!entry->e_value_inum) + continue; + error = ext4_xattr_inode_iget(inode, + le32_to_cpu(entry->e_value_inum), + le32_to_cpu(entry->e_hash), + &ea_inode); + if (error) + continue; + ext4_xattr_inode_free_quota(inode, ea_inode, + le32_to_cpu(entry->e_value_size)); + iput(ea_inode); + } + + } + + ext4_xattr_release_block(handle, inode, bh, ea_inode_array, + extra_credits); + /* + * Update i_file_acl value in the same transaction that releases + * block. + */ + EXT4_I(inode)->i_file_acl = 0; + error = ext4_mark_inode_dirty(handle, inode); + if (error) { + EXT4_ERROR_INODE(inode, "mark inode dirty (error %d)", + error); + goto cleanup; + } + ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_XATTR, handle); + } + error = 0; +cleanup: + brelse(iloc.bh); + brelse(bh); + return error; +} + +void ext4_xattr_inode_array_free(struct ext4_xattr_inode_array *ea_inode_array) +{ + int idx; + + if (ea_inode_array == NULL) + return; + + for (idx = 0; idx < ea_inode_array->count; ++idx) + iput(ea_inode_array->inodes[idx]); + kfree(ea_inode_array); +} + +/* + * ext4_xattr_block_cache_insert() + * + * Create a new entry in the extended attribute block 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_block_cache_insert(struct mb_cache *ea_block_cache, + struct buffer_head *bh) +{ + struct ext4_xattr_header *header = BHDR(bh); + __u32 hash = le32_to_cpu(header->h_hash); + int reusable = le32_to_cpu(header->h_refcount) < + EXT4_XATTR_REFCOUNT_MAX; + int error; + + if (!ea_block_cache) + return; + error = mb_cache_entry_create(ea_block_cache, GFP_NOFS, hash, + bh->b_blocknr, reusable); + if (error) { + if (error == -EBUSY) + ea_bdebug(bh, "already in cache"); + } else + ea_bdebug(bh, "inserting [%x]", (int)hash); +} + +/* + * 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 || + entry1->e_value_inum != entry2->e_value_inum || + memcmp(entry1->e_name, entry2->e_name, entry1->e_name_len)) + return 1; + if (!entry1->e_value_inum && + 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_block_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_block_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; + struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode); + + if (!ea_block_cache) + return NULL; + if (!header->h_hash) + return NULL; /* never share */ + ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); + ce = mb_cache_entry_find_first(ea_block_cache, hash); + while (ce) { + struct buffer_head *bh; + + bh = ext4_sb_bread(inode->i_sb, ce->e_value, REQ_PRIO); + if (IS_ERR(bh)) { + if (PTR_ERR(bh) == -ENOMEM) + return NULL; + bh = NULL; + EXT4_ERROR_INODE(inode, "block %lu read error", + (unsigned long)ce->e_value); + } else if (ext4_xattr_cmp(header, BHDR(bh)) == 0) { + *pce = ce; + return bh; + } + brelse(bh); + ce = mb_cache_entry_find_next(ea_block_cache, ce); + } + return NULL; +} + +#define NAME_HASH_SHIFT 5 +#define VALUE_HASH_SHIFT 16 + +/* + * ext4_xattr_hash_entry() + * + * Compute the hash of an extended attribute. + */ +static __le32 ext4_xattr_hash_entry(char *name, size_t name_len, __le32 *value, + size_t value_count) +{ + __u32 hash = 0; + + while (name_len--) { + hash = (hash << NAME_HASH_SHIFT) ^ + (hash >> (8*sizeof(hash) - NAME_HASH_SHIFT)) ^ + *name++; + } + while (value_count--) { + hash = (hash << VALUE_HASH_SHIFT) ^ + (hash >> (8*sizeof(hash) - VALUE_HASH_SHIFT)) ^ + le32_to_cpu(*value++); + } + return 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 *here; + __u32 hash = 0; + + 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 + +#define HASH_BUCKET_BITS 10 + +struct mb_cache * +ext4_xattr_create_cache(void) +{ + return mb_cache_create(HASH_BUCKET_BITS); +} + +void ext4_xattr_destroy_cache(struct mb_cache *cache) +{ + if (cache) + mb_cache_destroy(cache); +} + |