From 4f764e5153616fccaed38e7524d6f5f89a49a060 Mon Sep 17 00:00:00 2001 From: Filipe Manana Date: Mon, 23 Feb 2015 19:53:35 +0000 Subject: [PATCH] Btrfs: remove deleted xattrs on fsync log replay If we deleted xattrs from a file and fsynced the file, after a log replay the xattrs would remain associated to the file. This was an unexpected behaviour and differs from what other filesystems do, such as for example xfs and ext3/4. Fix this by, on fsync log replay, check if every xattr in the fs/subvol tree (that belongs to a logged inode) has a matching xattr in the log, and if it does not, delete it from the fs/subvol tree. This is a similar approach to what we do for dentries when we replay a directory from the fsync log. This issue is trivial to reproduce, and the following excerpt from my test for xfstests triggers the issue: _crash_and_mount() { # Simulate a crash/power loss. _load_flakey_table $FLAKEY_DROP_WRITES _unmount_flakey _load_flakey_table $FLAKEY_ALLOW_WRITES _mount_flakey } rm -f $seqres.full _scratch_mkfs >> $seqres.full 2>&1 _init_flakey _mount_flakey # Create out test file and add 3 xattrs to it. touch $SCRATCH_MNT/foobar $SETFATTR_PROG -n user.attr1 -v val1 $SCRATCH_MNT/foobar $SETFATTR_PROG -n user.attr2 -v val2 $SCRATCH_MNT/foobar $SETFATTR_PROG -n user.attr3 -v val3 $SCRATCH_MNT/foobar # Make sure everything is durably persisted. sync # Now delete the second xattr and fsync the inode. $SETFATTR_PROG -x user.attr2 $SCRATCH_MNT/foobar $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar _crash_and_mount # After the fsync log is replayed, the file should have only 2 xattrs, the ones # named user.attr1 and user.attr3. The btrfs fsync log replay bug left the file # with the 3 xattrs that we had before deleting the second one and fsyncing the # file. echo "xattr names and values after first fsync log replay:" $GETFATTR_PROG --absolute-names --dump $SCRATCH_MNT/foobar | _filter_scratch # Now write some data to our file, fsync it, remove the first xattr, add a new # hard link to our file and commit the fsync log by fsyncing some other new # file. This is to verify that after log replay our first xattr does not exist # anymore. echo "hello world!" >> $SCRATCH_MNT/foobar $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foobar $SETFATTR_PROG -x user.attr1 $SCRATCH_MNT/foobar ln $SCRATCH_MNT/foobar $SCRATCH_MNT/foobar_link touch $SCRATCH_MNT/qwerty $XFS_IO_PROG -c "fsync" $SCRATCH_MNT/qwerty _crash_and_mount # Now only the xattr with name user.attr3 should be set in our file. echo "xattr names and values after second fsync log replay:" $GETFATTR_PROG --absolute-names --dump $SCRATCH_MNT/foobar | _filter_scratch status=0 exit The expected golden output, which is produced with this patch applied or when testing against xfs or ext3/4, is: xattr names and values after first fsync log replay: # file: SCRATCH_MNT/foobar user.attr1="val1" user.attr3="val3" xattr names and values after second fsync log replay: # file: SCRATCH_MNT/foobar user.attr3="val3" Without this patch applied, the output is: xattr names and values after first fsync log replay: # file: SCRATCH_MNT/foobar user.attr1="val1" user.attr2="val2" user.attr3="val3" xattr names and values after second fsync log replay: # file: SCRATCH_MNT/foobar user.attr1="val1" user.attr2="val2" user.attr3="val3" A patch with a test case for xfstests follows soon. Signed-off-by: Filipe Manana Signed-off-by: Chris Mason --- fs/btrfs/tree-log.c | 123 ++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 109 insertions(+), 14 deletions(-) diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 066e754..6c951593 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -1951,6 +1951,104 @@ out: return ret; } +static int replay_xattr_deletes(struct btrfs_trans_handle *trans, + struct btrfs_root *root, + struct btrfs_root *log, + struct btrfs_path *path, + const u64 ino) +{ + struct btrfs_key search_key; + struct btrfs_path *log_path; + int i; + int nritems; + int ret; + + log_path = btrfs_alloc_path(); + if (!log_path) + return -ENOMEM; + + search_key.objectid = ino; + search_key.type = BTRFS_XATTR_ITEM_KEY; + search_key.offset = 0; +again: + ret = btrfs_search_slot(NULL, root, &search_key, path, 0, 0); + if (ret < 0) + goto out; +process_leaf: + nritems = btrfs_header_nritems(path->nodes[0]); + for (i = path->slots[0]; i < nritems; i++) { + struct btrfs_key key; + struct btrfs_dir_item *di; + struct btrfs_dir_item *log_di; + u32 total_size; + u32 cur; + + btrfs_item_key_to_cpu(path->nodes[0], &key, i); + if (key.objectid != ino || key.type != BTRFS_XATTR_ITEM_KEY) { + ret = 0; + goto out; + } + + di = btrfs_item_ptr(path->nodes[0], i, struct btrfs_dir_item); + total_size = btrfs_item_size_nr(path->nodes[0], i); + cur = 0; + while (cur < total_size) { + u16 name_len = btrfs_dir_name_len(path->nodes[0], di); + u16 data_len = btrfs_dir_data_len(path->nodes[0], di); + u32 this_len = sizeof(*di) + name_len + data_len; + char *name; + + name = kmalloc(name_len, GFP_NOFS); + if (!name) { + ret = -ENOMEM; + goto out; + } + read_extent_buffer(path->nodes[0], name, + (unsigned long)(di + 1), name_len); + + log_di = btrfs_lookup_xattr(NULL, log, log_path, ino, + name, name_len, 0); + btrfs_release_path(log_path); + if (!log_di) { + /* Doesn't exist in log tree, so delete it. */ + btrfs_release_path(path); + di = btrfs_lookup_xattr(trans, root, path, ino, + name, name_len, -1); + kfree(name); + if (IS_ERR(di)) { + ret = PTR_ERR(di); + goto out; + } + ASSERT(di); + ret = btrfs_delete_one_dir_name(trans, root, + path, di); + if (ret) + goto out; + btrfs_release_path(path); + search_key = key; + goto again; + } + kfree(name); + if (IS_ERR(log_di)) { + ret = PTR_ERR(log_di); + goto out; + } + cur += this_len; + di = (struct btrfs_dir_item *)((char *)di + this_len); + } + } + ret = btrfs_next_leaf(root, path); + if (ret > 0) + ret = 0; + else if (ret == 0) + goto process_leaf; +out: + btrfs_free_path(log_path); + btrfs_release_path(path); + return ret; +} + + /* * deletion replay happens before we copy any new directory items * out of the log or out of backreferences from inodes. It @@ -2104,6 +2202,10 @@ static int replay_one_buffer(struct btrfs_root *log, struct extent_buffer *eb, inode_item = btrfs_item_ptr(eb, i, struct btrfs_inode_item); + ret = replay_xattr_deletes(wc->trans, root, log, + path, key.objectid); + if (ret) + break; mode = btrfs_inode_mode(eb, inode_item); if (S_ISDIR(mode)) { ret = replay_dir_deletes(wc->trans, @@ -4072,10 +4174,8 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans, if (S_ISDIR(inode->i_mode)) { int max_key_type = BTRFS_DIR_LOG_INDEX_KEY; - if (inode_only == LOG_INODE_EXISTS) { - max_key_type = BTRFS_INODE_EXTREF_KEY; - max_key.type = max_key_type; - } + if (inode_only == LOG_INODE_EXISTS) + max_key_type = BTRFS_XATTR_ITEM_KEY; ret = drop_objectid_items(trans, log, path, ino, max_key_type); } else { if (inode_only == LOG_INODE_EXISTS) { @@ -4100,7 +4200,7 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans, if (test_bit(BTRFS_INODE_NEEDS_FULL_SYNC, &BTRFS_I(inode)->runtime_flags)) { if (inode_only == LOG_INODE_EXISTS) { - max_key.type = BTRFS_INODE_EXTREF_KEY; + max_key.type = BTRFS_XATTR_ITEM_KEY; ret = drop_objectid_items(trans, log, path, ino, max_key.type); } else { @@ -4111,17 +4211,12 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans, ret = btrfs_truncate_inode_items(trans, log, inode, 0, 0); } - } else if (test_bit(BTRFS_INODE_COPY_EVERYTHING, - &BTRFS_I(inode)->runtime_flags) || + } else if (test_and_clear_bit(BTRFS_INODE_COPY_EVERYTHING, + &BTRFS_I(inode)->runtime_flags) || inode_only == LOG_INODE_EXISTS) { - if (inode_only == LOG_INODE_ALL) { - clear_bit(BTRFS_INODE_COPY_EVERYTHING, - &BTRFS_I(inode)->runtime_flags); + if (inode_only == LOG_INODE_ALL) fast_search = true; - max_key.type = BTRFS_XATTR_ITEM_KEY; - } else { - max_key.type = BTRFS_INODE_EXTREF_KEY; - } + max_key.type = BTRFS_XATTR_ITEM_KEY; ret = drop_objectid_items(trans, log, path, ino, max_key.type); } else { -- 2.7.4