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| author | Frank Mayhar <fmayhar@google.com> | 2010-05-17 08:00:00 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2010-05-17 08:00:00 -0400 |
| commit | 14ece1028b3ed53ffec1b1213ffc6acaf79ad77c (patch) | |
| tree | 8f5a13487139c68ef775c9d39b7be83386fdae06 /fs/ext4/fsync.c | |
| parent | 60e6679e28518ccd67169c4a539d8cc7490eb8a6 (diff) | |
| download | linux-14ece1028b3ed53ffec1b1213ffc6acaf79ad77c.tar.gz linux-14ece1028b3ed53ffec1b1213ffc6acaf79ad77c.tar.bz2 linux-14ece1028b3ed53ffec1b1213ffc6acaf79ad77c.zip | |
ext4: Make fsync sync new parent directories in no-journal mode
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 <fmayhar@google.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/fsync.c')
| -rw-r--r-- | fs/ext4/fsync.c | 31 |
1 files changed, 29 insertions, 2 deletions
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c index 6ca7b6e59d83..e187f87acec0 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: |