diff options
Diffstat (limited to 'fs/ext2')
| -rw-r--r-- | fs/ext2/xattr.c | 58 |
1 files changed, 29 insertions, 29 deletions
diff --git a/fs/ext2/xattr.c b/fs/ext2/xattr.c index 37ce495eb279..641abfa4b718 100644 --- a/fs/ext2/xattr.c +++ b/fs/ext2/xattr.c @@ -522,17 +522,18 @@ bad_block: lock_buffer(bh); if (header->h_refcount == cpu_to_le32(1)) { __u32 hash = le32_to_cpu(header->h_hash); + struct mb_cache_entry *oe; - ea_bdebug(bh, "modifying in-place"); + oe = mb_cache_entry_delete_or_get(EA_BLOCK_CACHE(inode), + hash, bh->b_blocknr); + if (!oe) { + ea_bdebug(bh, "modifying in-place"); + goto update_block; + } /* - * This must happen under buffer lock for - * ext2_xattr_set2() to reliably detect modified block + * Someone is trying to reuse the block, leave it alone */ - mb_cache_entry_delete(EA_BLOCK_CACHE(inode), hash, - bh->b_blocknr); - - /* keep the buffer locked while modifying it. */ - goto update_block; + mb_cache_entry_put(EA_BLOCK_CACHE(inode), oe); } unlock_buffer(bh); ea_bdebug(bh, "cloning"); @@ -656,16 +657,29 @@ static void ext2_xattr_release_block(struct inode *inode, { struct mb_cache *ea_block_cache = EA_BLOCK_CACHE(inode); +retry_ref: lock_buffer(bh); if (HDR(bh)->h_refcount == cpu_to_le32(1)) { __u32 hash = le32_to_cpu(HDR(bh)->h_hash); + struct mb_cache_entry *oe; /* - * This must happen under buffer lock for - * ext2_xattr_set2() to reliably detect freed block + * This must happen under buffer lock to properly + * serialize with ext2_xattr_set() reusing the block. */ - mb_cache_entry_delete(ea_block_cache, hash, - bh->b_blocknr); + oe = mb_cache_entry_delete_or_get(ea_block_cache, hash, + bh->b_blocknr); + if (oe) { + /* + * Someone is trying to reuse the block. Wait + * and retry. + */ + unlock_buffer(bh); + mb_cache_entry_wait_unused(oe); + mb_cache_entry_put(ea_block_cache, oe); + goto retry_ref; + } + /* Free the old block. */ ea_bdebug(bh, "freeing"); ext2_free_blocks(inode, bh->b_blocknr, 1); @@ -929,7 +943,7 @@ ext2_xattr_cache_find(struct inode *inode, struct ext2_xattr_header *header) 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(ea_block_cache, hash); while (ce) { struct buffer_head *bh; @@ -941,22 +955,8 @@ again: inode->i_ino, (unsigned long) ce->e_value); } else { lock_buffer(bh); - /* - * 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(ea_block_cache, ce); - unlock_buffer(bh); - brelse(bh); - goto again; - } else if (le32_to_cpu(HDR(bh)->h_refcount) > - EXT2_XATTR_REFCOUNT_MAX) { + if (le32_to_cpu(HDR(bh)->h_refcount) > + EXT2_XATTR_REFCOUNT_MAX) { ea_idebug(inode, "block %ld refcount %d>%d", (unsigned long) ce->e_value, le32_to_cpu(HDR(bh)->h_refcount), |