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| author | Artem Bityutskiy <artem.bityutskiy@linux.intel.com> | 2012-07-22 20:33:31 -0400 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2012-07-22 20:33:31 -0400 |
| commit | 58c5873a769987e36265d1523d2aa5bdc18f32bd (patch) | |
| tree | 14bb293c91b8da4d1e6874fe324667da4a16e799 | |
| parent | 044ce47fec90ec0f25605e87a5d72cca14568bc3 (diff) | |
| download | linux-58c5873a769987e36265d1523d2aa5bdc18f32bd.tar.bz2 | |
ext4: remove unnecessary superblock dirtying
This patch changes the 'ext4_handle_dirty_super()' function which
submits the superblock for I/O in the following cases:
1. When creating the first large file on a file system without
EXT4_FEATURE_RO_COMPAT_LARGE_FILE feature.
2. When re-sizing the file-system.
3. When creating an xattr on a file-system without the
EXT4_FEATURE_COMPAT_EXT_ATTR feature.
If the file-system has journal enabled, the superblock is written via
the journal. We do not modify this path.
If the file-system has no journal, this function, falls back to just
marking the superblock as dirty using the 's_dirt' superblock
flag. This means that it delays the actual superblock I/O submission
by 5 seconds (default setting). Namely, the 'sync_supers()' kernel
thread will call 'ext4_write_super()' later and will actually submit
the superblock for I/O.
And this is the behavior this patch modifies: we stop using 's_dirt'
and just mark the superblock buffer as dirty right away. Indeed, all 3
cases above are extremely rare and it does not add any value to delay
the I/O submission for them.
Note: 'ext4_handle_dirty_super()' executes
'__ext4_handle_dirty_super()' with 'now = 0'. This patch basically
makes the 'now' argument unneeded and it will be deleted in one of the
next patches.
This patch also removes 's_dirt' condition on the unmount path because
we never set it anymore, so we should not test it.
Tested using xfstests for both journalled and non-journalled ext4.
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
| -rw-r--r-- | fs/ext4/ext4_jbd2.c | 5 | ||||
| -rw-r--r-- | fs/ext4/super.c | 2 |
2 files changed, 3 insertions, 4 deletions
diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c index 90f7c2e84db1..c19ab6addb24 100644 --- a/fs/ext4/ext4_jbd2.c +++ b/fs/ext4/ext4_jbd2.c @@ -151,11 +151,10 @@ int __ext4_handle_dirty_super(const char *where, unsigned int line, if (err) ext4_journal_abort_handle(where, line, __func__, bh, handle, err); - } else if (now) { + } else { ext4_superblock_csum_set(sb, (struct ext4_super_block *)bh->b_data); mark_buffer_dirty(bh); - } else - sb->s_dirt = 1; + } return err; } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index bebf8e5bf087..662e93e8c25b 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -896,7 +896,7 @@ static void ext4_put_super(struct super_block *sb) EXT4_CLEAR_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_RECOVER); es->s_state = cpu_to_le16(sbi->s_mount_state); } - if (sb->s_dirt || !(sb->s_flags & MS_RDONLY)) + if (!(sb->s_flags & MS_RDONLY)) ext4_commit_super(sb, 1); if (sbi->s_proc) { |