From: Harshad Shirwadkar harshadshirwadkar@gmail.com
commit 8210bb29c1b66200cff7b25febcf6e39baf49fbf upstream.
This patch adds rename whiteout support in fast commits. Note that the whiteout object that gets created is actually char device. Which imples, the function ext4_inode_journal_mode(struct inode *inode) would return "JOURNAL_DATA" for this inode. This has a consequence in fast commit code that it will make creation of the whiteout object a fast-commit ineligible behavior and thus will fall back to full commits. With this patch, this can be observed by running fast commits with rename whiteout and seeing the stats generated by ext4_fc_stats tracepoint as follows:
ext4_fc_stats: dev 254:32 fc ineligible reasons: XATTR:0, CROSS_RENAME:0, JOURNAL_FLAG_CHANGE:0, NO_MEM:0, SWAP_BOOT:0, RESIZE:0, RENAME_DIR:0, FALLOC_RANGE:0, INODE_JOURNAL_DATA:16; num_commits:6, ineligible: 6, numblks: 3
So in short, this patch guarantees that in case of rename whiteout, we fall back to full commits.
Amir mentioned that instead of creating a new whiteout object for every rename, we can create a static whiteout object with irrelevant nlink. That will make fast commits to not fall back to full commit. But until this happens, this patch will ensure correctness by falling back to full commits.
Fixes: 8016e29f4362 ("ext4: fast commit recovery path") Cc: stable@kernel.org Signed-off-by: Harshad Shirwadkar harshadshirwadkar@gmail.com Link: https://lore.kernel.org/r/20210316221921.1124955-1-harshadshirwadkar@gmail.c... Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/ext4.h | 2 ++ fs/ext4/fast_commit.c | 9 +++++++-- fs/ext4/namei.c | 3 +++ 3 files changed, 12 insertions(+), 2 deletions(-)
--- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2762,6 +2762,8 @@ void __ext4_fc_track_link(handle_t *hand struct dentry *dentry); void ext4_fc_track_unlink(handle_t *handle, struct dentry *dentry); void ext4_fc_track_link(handle_t *handle, struct dentry *dentry); +void __ext4_fc_track_create(handle_t *handle, struct inode *inode, + struct dentry *dentry); void ext4_fc_track_create(handle_t *handle, struct dentry *dentry); void ext4_fc_track_inode(handle_t *handle, struct inode *inode); void ext4_fc_mark_ineligible(struct super_block *sb, int reason); --- a/fs/ext4/fast_commit.c +++ b/fs/ext4/fast_commit.c @@ -452,10 +452,10 @@ void ext4_fc_track_link(handle_t *handle __ext4_fc_track_link(handle, d_inode(dentry), dentry); }
-void ext4_fc_track_create(handle_t *handle, struct dentry *dentry) +void __ext4_fc_track_create(handle_t *handle, struct inode *inode, + struct dentry *dentry) { struct __track_dentry_update_args args; - struct inode *inode = d_inode(dentry); int ret;
args.dentry = dentry; @@ -466,6 +466,11 @@ void ext4_fc_track_create(handle_t *hand trace_ext4_fc_track_create(inode, dentry, ret); }
+void ext4_fc_track_create(handle_t *handle, struct dentry *dentry) +{ + __ext4_fc_track_create(handle, d_inode(dentry), dentry); +} + /* __track_fn for inode tracking */ static int __track_inode(struct inode *inode, void *arg, bool update) { --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -3864,6 +3864,7 @@ static int ext4_rename(struct inode *old retval = ext4_mark_inode_dirty(handle, whiteout); if (unlikely(retval)) goto end_rename; + } if (!new.bh) { retval = ext4_add_entry(handle, new.dentry, old.inode); @@ -3937,6 +3938,8 @@ static int ext4_rename(struct inode *old ext4_fc_track_unlink(handle, new.dentry); __ext4_fc_track_link(handle, old.inode, new.dentry); __ext4_fc_track_unlink(handle, old.inode, old.dentry); + if (whiteout) + __ext4_fc_track_create(handle, whiteout, old.dentry); }
if (new.inode) {