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    Subject[PATCH 3.4 026/146] ext4: make fsync to sync parent dir in no-journal for real this time
    Date
    From: Lukas Czerner <lczerner@redhat.com>

    3.4.109-rc1 review patch. If anyone has any objections, please let me know.

    ------------------


    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>
    [lizf: Backported to 3.4: remove a change from return to goto, as that
    doesn't exist in 3.4]
    Signed-off-by: Zefan Li <lizefan@huawei.com>
    ---
    fs/ext4/namei.c | 18 ++++++++++--------
    1 file changed, 10 insertions(+), 8 deletions(-)

    diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
    index dc58523..e1e1d46 100644
    --- a/fs/ext4/namei.c
    +++ b/fs/ext4/namei.c
    @@ -1469,7 +1469,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
    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 super_block *sb;
    int retval;
    @@ -1484,7 +1484,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
    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);
    @@ -1495,14 +1495,15 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
    if(!bh)
    return retval;
    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, &retval);
    @@ -1512,6 +1513,7 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry,
    de->inode = 0;
    de->rec_len = ext4_rec_len_to_disk(blocksize, blocksize);
    retval = add_dirent_to_buf(handle, dentry, inode, de, bh);
    +out:
    brelse(bh);
    if (retval == 0)
    ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY);
    --
    1.9.1


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