[PATCH 3.14 48/92] ext4: make fsync to sync parent dir in no-journal for real this time

Greg Kroah-Hartman
2015-05-02T20:15:36Z

From: Lukas Czerner <lczerner@redhat.com>

commit e12fb97222fc41e8442896934f76d39ef99b590a upstream.

Previously commit 14ece1028b3ed53ffec1b1213ffc6acaf79ad77c added a
support for for syncing parent directory of newly created inodes to
make sure that the inode is not lost after a power failure in
no-journal mode.

However this does not work in majority of cases, namely:
- if the directory has inline data
- if the directory is already indexed
- if the directory already has at least one block and:
- the new entry fits into it
- or we've successfully converted it to indexed

So in those cases we might lose the inode entirely even after fsync in
the no-journal mode. This also includes ext2 default mode obviously.

I've noticed this while running xfstest generic/321 and even though the
test should fail (we need to run fsck after a crash in no-journal mode)
I could not find a newly created entries even when if it was fsynced
before.

Fix this by adjusting the ext4_add_entry() successful exit paths to set
the inode EXT4_STATE_NEWENTRY so that fsync has the chance to fsync the
parent directory as well.

Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Frank Mayhar <fmayhar@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
fs/ext4/namei.c | 20 +++++++++++---------
1 file changed, 11 insertions(+), 9 deletions(-)

--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1869,7 +1869,7 @@ static int ext4_add_entry(handle_t *hand
struct inode *inode)
{
struct inode *dir = dentry->d_parent->d_inode;
- struct buffer_head *bh;
+ struct buffer_head *bh = NULL;
struct ext4_dir_entry_2 *de;
struct ext4_dir_entry_tail *t;
struct super_block *sb;
@@ -1893,14 +1893,14 @@ static int ext4_add_entry(handle_t *hand
return retval;
if (retval == 1) {
retval = 0;
- return retval;
+ goto out;
}
}

if (is_dx(dir)) {
retval = ext4_dx_add_entry(handle, dentry, inode);
if (!retval || (retval != ERR_BAD_DX_DIR))
- return retval;
+ goto out;
ext4_clear_inode_flag(dir, EXT4_INODE_INDEX);
dx_fallback++;
ext4_mark_inode_dirty(handle, dir);
@@ -1912,14 +1912,15 @@ static int ext4_add_entry(handle_t *hand
return PTR_ERR(bh);

retval = add_dirent_to_buf(handle, dentry, inode, NULL, bh);
- if (retval != -ENOSPC) {
- brelse(bh);
- return retval;
- }
+ if (retval != -ENOSPC)
+ goto out;

if (blocks == 1 && !dx_fallback &&
- EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX))
- return make_indexed_dir(handle, dentry, inode, bh);
+ EXT4_HAS_COMPAT_FEATURE(sb, EXT4_FEATURE_COMPAT_DIR_INDEX)) {
+ retval = make_indexed_dir(handle, dentry, inode, bh);
+ bh = NULL; /* make_indexed_dir releases bh */
+ goto out;
+ }
brelse(bh);
}
bh = ext4_append(handle, dir, &block);
@@ -1935,6 +1936,7 @@ static int ext4_add_entry(handle_t *hand
}

retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
+out:
brelse(bh);
if (retval == 0)
ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);