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authorArtem Bityutskiy <artem.bityutskiy@linux.intel.com>2012-07-22 20:33:31 -0400
committerTheodore Ts'o <tytso@mit.edu>2012-07-22 20:33:31 -0400
commit58c5873a769987e36265d1523d2aa5bdc18f32bd (patch)
tree14bb293c91b8da4d1e6874fe324667da4a16e799
parent044ce47fec90ec0f25605e87a5d72cca14568bc3 (diff)
downloadlinux-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.c5
-rw-r--r--fs/ext4/super.c2
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) {