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| author | Omar Sandoval <osandov@fb.com> | 2019-08-15 14:04:02 -0700 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2019-09-09 14:59:17 +0200 |
| commit | c09767a8960ca0500fb636bf73686723337debf4 (patch) | |
| tree | 7632ca4af900175285253b2f7b45057d8fe81738 /fs | |
| parent | c82f823c9b006c31059341af41da9f8b2e3e64d9 (diff) | |
| download | linux-stable-c09767a8960ca0500fb636bf73686723337debf4.tar.gz linux-stable-c09767a8960ca0500fb636bf73686723337debf4.tar.bz2 linux-stable-c09767a8960ca0500fb636bf73686723337debf4.zip | |
btrfs: use correct count in btrfs_file_write_iter()
generic_write_checks() may modify iov_iter_count(), so we must get the
count after the call, not before. Using the wrong one has a couple of
consequences:
1. We check a longer range in check_can_nocow() for nowait than we're
actually writing.
2. We create extra hole extent maps in btrfs_cont_expand(). As far as I
can tell, this is harmless, but I might be missing something.
These issues are pretty minor, but let's fix it before something more
important trips on it.
Fixes: edf064e7c6fe ("btrfs: nowait aio support")
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/file.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 1cb694c96500..25df5b03b591 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1885,7 +1885,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host); ssize_t err; loff_t pos; - size_t count = iov_iter_count(from); + size_t count; loff_t oldsize; int clean_page = 0; @@ -1906,6 +1906,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, } pos = iocb->ki_pos; + count = iov_iter_count(from); if (iocb->ki_flags & IOCB_NOWAIT) { /* * We will allocate space in case nodatacow is not set, |