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Commit 58a9d3d8db06ca2ec31f64ec49ab0aeb89971b85

Authored by Richard Kennedy
Committed by Linus Torvalds
1 parent ec95f53aa6
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

fs-writeback: check sync bit earlier in inode_wait_for_writeback 

When wb_writeback() hasn't written anything it will re-acquire the inode
lock before calling inode_wait_for_writeback.

This change tests the sync bit first so that is doesn't need to drop &
re-acquire the lock if the inode became available while wb_writeback() was
waiting to get the lock.

Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Showing 1 changed file with 2 additions and 2 deletions Side-by-side Diff

... ... @@ -409,11 +409,11 @@
409 409 wait_queue_head_t *wqh;
410 410  
411 411 wqh = bit_waitqueue(&inode->i_state, __I_SYNC);
412   - do {
  412 + while (inode->i_state & I_SYNC) {
413 413 spin_unlock(&inode_lock);
414 414 __wait_on_bit(wqh, &wq, inode_wait, TASK_UNINTERRUPTIBLE);
415 415 spin_lock(&inode_lock);
416   - } while (inode->i_state & I_SYNC);
  416 + }
417 417 }
418 418  
419 419 /*