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| author | Matthew Bobrowski <mbobrowski@mbobrowski.org> | 2019-11-05 14:59:37 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-01-04 21:17:13 +0300 |
| commit | e48a6034482babeccdd6a2aac6f3b10beda35f26 (patch) | |
| tree | b3726ee9858ac57e36472b52e7f548891d8c3c5f /fs/ext4 | |
| parent | 339a860cdd0726477131c67e1d618844f2b64610 (diff) | |
| download | linux-e48a6034482babeccdd6a2aac6f3b10beda35f26.tar.xz | |
ext4: iomap that extends beyond EOF should be marked dirty
[ Upstream commit 2e9b51d78229d5145725a481bb5464ebc0a3f9b2 ]
This patch addresses what Dave Chinner had discovered and fixed within
commit: 7684e2c4384d. This changes does not have any user visible
impact for ext4 as none of the current users of ext4_iomap_begin()
that extend files depend on IOMAP_F_DIRTY.
When doing a direct IO that spans the current EOF, and there are
written blocks beyond EOF that extend beyond the current write, the
only metadata update that needs to be done is a file size extension.
However, we don't mark such iomaps as IOMAP_F_DIRTY to indicate that
there is IO completion metadata updates required, and hence we may
fail to correctly sync file size extensions made in IO completion when
O_DSYNC writes are being used and the hardware supports FUA.
Hence when setting IOMAP_F_DIRTY, we need to also take into account
whether the iomap spans the current EOF. If it does, then we need to
mark it dirty so that IO completion will call generic_write_sync() to
flush the inode size update to stable storage correctly.
Signed-off-by: Matthew Bobrowski <mbobrowski@mbobrowski.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani <riteshh@linux.ibm.com>
Link: https://lore.kernel.org/r/8b43ee9ee94bee5328da56ba0909b7d2229ef150.1572949325.git.mbobrowski@mbobrowski.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'fs/ext4')
| -rw-r--r-- | fs/ext4/inode.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index b10aa115eade..8bba6cd5e870 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3532,8 +3532,14 @@ retry: return ret; } + /* + * Writes that span EOF might trigger an I/O size update on completion, + * so consider them to be dirty for the purposes of O_DSYNC, even if + * there is no other metadata changes being made or are pending here. + */ iomap->flags = 0; - if (ext4_inode_datasync_dirty(inode)) + if (ext4_inode_datasync_dirty(inode) || + offset + length > i_size_read(inode)) iomap->flags |= IOMAP_F_DIRTY; iomap->bdev = inode->i_sb->s_bdev; iomap->dax_dev = sbi->s_daxdev; |