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| author | Eric Sandeen <sandeen@redhat.com> | 2009-12-23 07:57:07 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2009-12-23 07:57:07 -0500 |
| commit | 17bd55d037a02b04d9119511cfd1a4b985d20f63 (patch) | |
| tree | ddbc227fffb84d1b95f5f8c48b627f88f3fd56ed | |
| parent | d3533d72e7478a61a3e1936956fc825289a2acf4 (diff) | |
| download | blackbird-op-linux-17bd55d037a02b04d9119511cfd1a4b985d20f63.tar.gz blackbird-op-linux-17bd55d037a02b04d9119511cfd1a4b985d20f63.zip | |
fs-writeback: Add helper function to start writeback if idle
ext4, at least, would like to start pushing on writeback if it starts
to get close to ENOSPC when reserving worst-case blocks for delalloc
writes. Writing out delalloc data will convert those worst-case
predictions into usually smaller actual usage, freeing up space
before we hit ENOSPC based on this speculation.
Thanks to Jens for the suggestion for the helper function,
& the naming help.
I've made the helper return status on whether writeback was
started even though I don't plan to use it in the ext4 patch;
it seems like it would be potentially useful to test this
in some cases.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Jan Kara <jack@suse.cz>
| -rw-r--r-- | fs/fs-writeback.c | 17 | ||||
| -rw-r--r-- | include/linux/writeback.h | 1 |
2 files changed, 18 insertions, 0 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 49bc1b8e8f19..f6c2155e0026 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -1187,6 +1187,23 @@ void writeback_inodes_sb(struct super_block *sb) EXPORT_SYMBOL(writeback_inodes_sb); /** + * writeback_inodes_sb_if_idle - start writeback if none underway + * @sb: the superblock + * + * Invoke writeback_inodes_sb if no writeback is currently underway. + * Returns 1 if writeback was started, 0 if not. + */ +int writeback_inodes_sb_if_idle(struct super_block *sb) +{ + if (!writeback_in_progress(sb->s_bdi)) { + writeback_inodes_sb(sb); + return 1; + } else + return 0; +} +EXPORT_SYMBOL(writeback_inodes_sb_if_idle); + +/** * sync_inodes_sb - sync sb inode pages * @sb: the superblock * diff --git a/include/linux/writeback.h b/include/linux/writeback.h index c18c008f4bbf..76e8903cd204 100644 --- a/include/linux/writeback.h +++ b/include/linux/writeback.h @@ -70,6 +70,7 @@ struct writeback_control { struct bdi_writeback; int inode_wait(void *); void writeback_inodes_sb(struct super_block *); +int writeback_inodes_sb_if_idle(struct super_block *); void sync_inodes_sb(struct super_block *); void writeback_inodes_wbc(struct writeback_control *wbc); long wb_do_writeback(struct bdi_writeback *wb, int force_wait); |
