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authorFrank Mayhar <fmayhar@google.com>2010-05-17 08:00:00 -0400
committerTheodore Ts'o <tytso@mit.edu>2010-05-17 08:00:00 -0400
commit14ece1028b3ed53ffec1b1213ffc6acaf79ad77c (patch)
tree8f5a13487139c68ef775c9d39b7be83386fdae06
parent60e6679e28518ccd67169c4a539d8cc7490eb8a6 (diff)
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>
-rw-r--r--fs/ext4/ext4.h1
-rw-r--r--fs/ext4/fsync.c31
-rw-r--r--fs/ext4/namei.c2
3 files changed, 32 insertions, 2 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 124ef771a618..60bd31026e7c 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1180,6 +1180,7 @@ 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 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:
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 83be743c8d1f..a43e6617b351 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1517,6 +1517,8 @@ 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;
}