From: Frank Mayhar <[email protected]> commit 14ece1028b3ed53ffec1b1213ffc6acaf79ad77c upstream.
Add a new ext4 state to tell us when a file has been newly created; use that state in ext4_sync_file in no-journal mode to tell us when we need to sync the parent directory as well as the inode and data itself. This fixes a problem in which a panic or power failure may lose the entire file even when using fsync, since the parent directory entry is lost. Addresses-Google-Bug: #2480057 Signed-off-by: Frank Mayhar <[email protected]> Signed-off-by: "Theodore Ts'o" <[email protected]> Signed-off-by: Paul Gortmaker <[email protected]> --- fs/ext4/ext4.h | 1 + fs/ext4/fsync.c | 31 +++++++++++++++++++++++++++++-- fs/ext4/namei.c | 2 ++ 3 files changed, 32 insertions(+), 2 deletions(-) diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index 2e31640..650ef37 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -1157,6 +1157,7 @@ enum { EXT4_STATE_DA_ALLOC_CLOSE, /* Alloc DA blks on close */ EXT4_STATE_EXT_MIGRATE, /* Inode is migrating */ EXT4_STATE_DIO_UNWRITTEN, /* need convert on dio done*/ + EXT4_STATE_NEWENTRY, /* File just added to dir */ }; #define EXT4_INODE_BIT_FNS(name, field) \ diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c index 42bd94a..6f25f9f 100644 --- a/fs/ext4/fsync.c +++ b/fs/ext4/fsync.c @@ -35,6 +35,29 @@ #include <trace/events/ext4.h> /* + * If we're not journaling and this is a just-created file, we have to + * sync our parent directory (if it was freshly created) since + * otherwise it will only be written by writeback, leaving a huge + * window during which a crash may lose the file. This may apply for + * the parent directory's parent as well, and so on recursively, if + * they are also freshly created. + */ +static void ext4_sync_parent(struct inode *inode) +{ + struct dentry *dentry = NULL; + + while (inode && ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) { + ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY); + dentry = list_entry(inode->i_dentry.next, + struct dentry, d_alias); + if (!dentry || !dentry->d_parent || !dentry->d_parent->d_inode) + break; + inode = dentry->d_parent->d_inode; + sync_mapping_buffers(inode->i_mapping); + } +} + +/* * akpm: A new design for ext4_sync_file(). * * This is only called from sys_fsync(), sys_fdatasync() and sys_msync(). @@ -67,8 +90,12 @@ int ext4_sync_file(struct file *file, struct dentry *dentry, int datasync) if (ret < 0) return ret; - if (!journal) - return simple_fsync(file, dentry, datasync); + if (!journal) { + ret = simple_fsync(file, dentry, datasync); + if (!ret && !list_empty(&inode->i_dentry)) + ext4_sync_parent(inode); + return ret; + } /* * data=writeback,ordered: diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index efab592..2f31631 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -1519,6 +1519,8 @@ static int ext4_add_entry(handle_t *handle, struct dentry *dentry, de->rec_len = ext4_rec_len_to_disk(blocksize, blocksize); retval = add_dirent_to_buf(handle, dentry, inode, de, bh); brelse(bh); + if (retval == 0) + ext4_set_inode_state(inode, EXT4_STATE_NEWENTRY); return retval; } -- 1.7.3.3 _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
