X-Git-Url: https://git.karo-electronics.de/?a=blobdiff_plain;f=fs%2Fext2%2Fxattr.c;h=1a5e3bff0b63c93454324a919fc1e008c0bc0193;hb=8f40842e4260f73792c156aded004197a19135ee;hp=f57a7aba32ebbd01aac9dde8783e5476b95a4c1d;hpb=3fdb74649b4f18ccaa88766750b616dec6acb5b0;p=karo-tx-linux.git diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c index f57a7aba32eb..1a5e3bff0b63 100644 --- a/fs/ext2/xattr.c +++ b/fs/ext2/xattr.c @@ -90,14 +90,12 @@ static int ext2_xattr_set2(struct inode *, struct buffer_head *, struct ext2_xattr_header *); -static int ext2_xattr_cache_insert(struct buffer_head *); +static int ext2_xattr_cache_insert(struct mb_cache *, struct buffer_head *); static struct buffer_head *ext2_xattr_cache_find(struct inode *, struct ext2_xattr_header *); static void ext2_xattr_rehash(struct ext2_xattr_header *, struct ext2_xattr_entry *); -static struct mb_cache *ext2_xattr_cache; - static const struct xattr_handler *ext2_xattr_handler_map[] = { [EXT2_XATTR_INDEX_USER] = &ext2_xattr_user_handler, #ifdef CONFIG_EXT2_FS_POSIX_ACL @@ -152,6 +150,7 @@ ext2_xattr_get(struct inode *inode, int name_index, const char *name, size_t name_len, size; char *end; int error; + struct mb_cache *ext2_mb_cache = EXT2_SB(inode->i_sb)->s_mb_cache; ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld", name_index, name, buffer, (long)buffer_size); @@ -196,7 +195,7 @@ bad_block: ext2_error(inode->i_sb, "ext2_xattr_get", goto found; entry = next; } - if (ext2_xattr_cache_insert(bh)) + if (ext2_xattr_cache_insert(ext2_mb_cache, bh)) ea_idebug(inode, "cache insert failed"); error = -ENODATA; goto cleanup; @@ -209,7 +208,7 @@ found: le16_to_cpu(entry->e_value_offs) + size > inode->i_sb->s_blocksize) goto bad_block; - if (ext2_xattr_cache_insert(bh)) + if (ext2_xattr_cache_insert(ext2_mb_cache, bh)) ea_idebug(inode, "cache insert failed"); if (buffer) { error = -ERANGE; @@ -247,6 +246,7 @@ ext2_xattr_list(struct dentry *dentry, char *buffer, size_t buffer_size) char *end; size_t rest = buffer_size; int error; + struct mb_cache *ext2_mb_cache = EXT2_SB(inode->i_sb)->s_mb_cache; ea_idebug(inode, "buffer=%p, buffer_size=%ld", buffer, (long)buffer_size); @@ -281,7 +281,7 @@ bad_block: ext2_error(inode->i_sb, "ext2_xattr_list", goto bad_block; entry = next; } - if (ext2_xattr_cache_insert(bh)) + if (ext2_xattr_cache_insert(ext2_mb_cache, bh)) ea_idebug(inode, "cache insert failed"); /* list the attribute names */ @@ -483,22 +483,23 @@ bad_block: ext2_error(sb, "ext2_xattr_set", /* Here we know that we can set the new attribute. */ if (header) { - struct mb_cache_entry *ce; - /* assert(header == HDR(bh)); */ - ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, - bh->b_blocknr); lock_buffer(bh); if (header->h_refcount == cpu_to_le32(1)) { + __u32 hash = le32_to_cpu(header->h_hash); + ea_bdebug(bh, "modifying in-place"); - if (ce) - mb_cache_entry_free(ce); + /* + * This must happen under buffer lock for + * ext2_xattr_set2() to reliably detect modified block + */ + mb_cache_entry_delete_block(EXT2_SB(sb)->s_mb_cache, + hash, bh->b_blocknr); + /* keep the buffer locked while modifying it. */ } else { int offset; - if (ce) - mb_cache_entry_release(ce); unlock_buffer(bh); ea_bdebug(bh, "cloning"); header = kmalloc(bh->b_size, GFP_KERNEL); @@ -626,6 +627,7 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, struct super_block *sb = inode->i_sb; struct buffer_head *new_bh = NULL; int error; + struct mb_cache *ext2_mb_cache = EXT2_SB(sb)->s_mb_cache; if (header) { new_bh = ext2_xattr_cache_find(inode, header); @@ -653,7 +655,7 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, don't need to change the reference count. */ new_bh = old_bh; get_bh(new_bh); - ext2_xattr_cache_insert(new_bh); + ext2_xattr_cache_insert(ext2_mb_cache, new_bh); } else { /* We need to allocate a new block */ ext2_fsblk_t goal = ext2_group_first_block_no(sb, @@ -674,7 +676,7 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, memcpy(new_bh->b_data, header, new_bh->b_size); set_buffer_uptodate(new_bh); unlock_buffer(new_bh); - ext2_xattr_cache_insert(new_bh); + ext2_xattr_cache_insert(ext2_mb_cache, new_bh); ext2_xattr_update_super_block(sb); } @@ -707,19 +709,21 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, error = 0; if (old_bh && old_bh != new_bh) { - struct mb_cache_entry *ce; - /* * If there was an old block and we are no longer using it, * release the old block. */ - ce = mb_cache_entry_get(ext2_xattr_cache, old_bh->b_bdev, - old_bh->b_blocknr); lock_buffer(old_bh); if (HDR(old_bh)->h_refcount == cpu_to_le32(1)) { + __u32 hash = le32_to_cpu(HDR(old_bh)->h_hash); + + /* + * This must happen under buffer lock for + * ext2_xattr_set2() to reliably detect freed block + */ + mb_cache_entry_delete_block(ext2_mb_cache, + hash, old_bh->b_blocknr); /* Free the old block. */ - if (ce) - mb_cache_entry_free(ce); ea_bdebug(old_bh, "freeing"); ext2_free_blocks(inode, old_bh->b_blocknr, 1); mark_inode_dirty(inode); @@ -730,8 +734,6 @@ ext2_xattr_set2(struct inode *inode, struct buffer_head *old_bh, } else { /* Decrement the refcount only. */ le32_add_cpu(&HDR(old_bh)->h_refcount, -1); - if (ce) - mb_cache_entry_release(ce); dquot_free_block_nodirty(inode, 1); mark_inode_dirty(inode); mark_buffer_dirty(old_bh); @@ -757,7 +759,6 @@ void ext2_xattr_delete_inode(struct inode *inode) { struct buffer_head *bh = NULL; - struct mb_cache_entry *ce; down_write(&EXT2_I(inode)->xattr_sem); if (!EXT2_I(inode)->i_file_acl) @@ -777,19 +778,22 @@ ext2_xattr_delete_inode(struct inode *inode) EXT2_I(inode)->i_file_acl); goto cleanup; } - ce = mb_cache_entry_get(ext2_xattr_cache, bh->b_bdev, bh->b_blocknr); lock_buffer(bh); if (HDR(bh)->h_refcount == cpu_to_le32(1)) { - if (ce) - mb_cache_entry_free(ce); + __u32 hash = le32_to_cpu(HDR(bh)->h_hash); + + /* + * This must happen under buffer lock for ext2_xattr_set2() to + * reliably detect freed block + */ + mb_cache_entry_delete_block(EXT2_SB(inode->i_sb)->s_mb_cache, + hash, bh->b_blocknr); ext2_free_blocks(inode, EXT2_I(inode)->i_file_acl, 1); get_bh(bh); bforget(bh); unlock_buffer(bh); } else { le32_add_cpu(&HDR(bh)->h_refcount, -1); - if (ce) - mb_cache_entry_release(ce); ea_bdebug(bh, "refcount now=%d", le32_to_cpu(HDR(bh)->h_refcount)); unlock_buffer(bh); @@ -805,18 +809,6 @@ cleanup: up_write(&EXT2_I(inode)->xattr_sem); } -/* - * ext2_xattr_put_super() - * - * This is called when a file system is unmounted. - */ -void -ext2_xattr_put_super(struct super_block *sb) -{ - mb_cache_shrink(sb->s_bdev); -} - - /* * ext2_xattr_cache_insert() * @@ -826,28 +818,20 @@ ext2_xattr_put_super(struct super_block *sb) * Returns 0, or a negative error number on failure. */ static int -ext2_xattr_cache_insert(struct buffer_head *bh) +ext2_xattr_cache_insert(struct mb_cache *cache, struct buffer_head *bh) { __u32 hash = le32_to_cpu(HDR(bh)->h_hash); - struct mb_cache_entry *ce; int error; - ce = mb_cache_entry_alloc(ext2_xattr_cache, GFP_NOFS); - if (!ce) - return -ENOMEM; - error = mb_cache_entry_insert(ce, bh->b_bdev, bh->b_blocknr, hash); + error = mb_cache_entry_create(cache, GFP_NOFS, hash, bh->b_blocknr, 1); if (error) { - mb_cache_entry_free(ce); if (error == -EBUSY) { ea_bdebug(bh, "already in cache (%d cache entries)", atomic_read(&ext2_xattr_cache->c_entry_count)); error = 0; } - } else { - ea_bdebug(bh, "inserting [%x] (%d cache entries)", (int)hash, - atomic_read(&ext2_xattr_cache->c_entry_count)); - mb_cache_entry_release(ce); - } + } else + ea_bdebug(bh, "inserting [%x]", (int)hash); return error; } @@ -904,22 +888,16 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header) { __u32 hash = le32_to_cpu(header->h_hash); struct mb_cache_entry *ce; + struct mb_cache *ext2_mb_cache = EXT2_SB(inode->i_sb)->s_mb_cache; if (!header->h_hash) return NULL; /* never share */ ea_idebug(inode, "looking for cached blocks [%x]", (int)hash); again: - ce = mb_cache_entry_find_first(ext2_xattr_cache, inode->i_sb->s_bdev, - hash); + ce = mb_cache_entry_find_first(ext2_mb_cache, hash); while (ce) { struct buffer_head *bh; - if (IS_ERR(ce)) { - if (PTR_ERR(ce) == -EAGAIN) - goto again; - break; - } - bh = sb_bread(inode->i_sb, ce->e_block); if (!bh) { ext2_error(inode->i_sb, "ext2_xattr_cache_find", @@ -927,7 +905,21 @@ again: inode->i_ino, (unsigned long) ce->e_block); } else { lock_buffer(bh); - if (le32_to_cpu(HDR(bh)->h_refcount) > + /* + * We have to be careful about races with freeing or + * rehashing of xattr block. Once we hold buffer lock + * xattr block's state is stable so we can check + * whether the block got freed / rehashed or not. + * Since we unhash mbcache entry under buffer lock when + * freeing / rehashing xattr block, checking whether + * entry is still hashed is reliable. + */ + if (hlist_bl_unhashed(&ce->e_hash_list)) { + mb_cache_entry_put(ext2_mb_cache, ce); + unlock_buffer(bh); + brelse(bh); + goto again; + } else if (le32_to_cpu(HDR(bh)->h_refcount) > EXT2_XATTR_REFCOUNT_MAX) { ea_idebug(inode, "block %ld refcount %d>%d", (unsigned long) ce->e_block, @@ -936,13 +928,14 @@ again: } else if (!ext2_xattr_cmp(header, HDR(bh))) { ea_bdebug(bh, "b_count=%d", atomic_read(&(bh->b_count))); - mb_cache_entry_release(ce); + mb_cache_entry_touch(ext2_mb_cache, ce); + mb_cache_entry_put(ext2_mb_cache, ce); return bh; } unlock_buffer(bh); brelse(bh); } - ce = mb_cache_entry_find_next(ce, inode->i_sb->s_bdev, hash); + ce = mb_cache_entry_find_next(ext2_mb_cache, ce); } return NULL; } @@ -1015,17 +1008,15 @@ static void ext2_xattr_rehash(struct ext2_xattr_header *header, #undef BLOCK_HASH_SHIFT -int __init -init_ext2_xattr(void) +#define HASH_BUCKET_BITS 10 + +struct mb_cache *ext2_xattr_create_cache(void) { - ext2_xattr_cache = mb_cache_create("ext2_xattr", 6); - if (!ext2_xattr_cache) - return -ENOMEM; - return 0; + return mb_cache_create(HASH_BUCKET_BITS); } -void -exit_ext2_xattr(void) +void ext2_xattr_destroy_cache(struct mb_cache *cache) { - mb_cache_destroy(ext2_xattr_cache); + if (cache) + mb_cache_destroy(cache); }