Patch "ext4: correct best extent lstart adjustment logic" has been added to the 6.7-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    ext4: correct best extent lstart adjustment logic

to the 6.7-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ext4-correct-best-extent-lstart-adjustment-logic.patch
and it can be found in the queue-6.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 693e37d089a206beb187344ac7d0ef46adacdc77
Author: Baokun Li <libaokun1@xxxxxxxxxx>
Date:   Thu Feb 1 22:18:45 2024 +0800

    ext4: correct best extent lstart adjustment logic
    
    [ Upstream commit 4fbf8bc733d14bceb16dda46a3f5e19c6a9621c5 ]
    
    When yangerkun review commit 93cdf49f6eca ("ext4: Fix best extent lstart
    adjustment logic in ext4_mb_new_inode_pa()"), it was found that the best
    extent did not completely cover the original request after adjusting the
    best extent lstart in ext4_mb_new_inode_pa() as follows:
    
      original request: 2/10(8)
      normalized request: 0/64(64)
      best extent: 0/9(9)
    
    When we check if best ex can be kept at start of goal, ac_o_ex.fe_logical
    is 2 less than the adjusted best extent logical end 9, so we think the
    adjustment is done. But obviously 0/9(9) doesn't cover 2/10(8), so we
    should determine here if the original request logical end is less than or
    equal to the adjusted best extent logical end.
    
    In addition, add a comment stating when adjusted best_ex will not cover
    the original request, and remove the duplicate assertion because adjusting
    lstart makes no change to b_ex.fe_len.
    
    Link: https://lore.kernel.org/r/3630fa7f-b432-7afd-5f79-781bc3b2c5ea@xxxxxxxxxx
    Fixes: 93cdf49f6eca ("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()")
    Cc:  <stable@xxxxxxxxxx>
    Signed-off-by: yangerkun <yangerkun@xxxxxxxxxx>
    Signed-off-by: Baokun Li <libaokun1@xxxxxxxxxx>
    Reviewed-by: Jan Kara <jack@xxxxxxx>
    Reviewed-by: Ojaswin Mujoo <ojaswin@xxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20240201141845.1879253-1-libaokun1@xxxxxxxxxx
    Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 7497a789d002e..38ec0fdb33953 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -5173,10 +5173,16 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 			.fe_len = ac->ac_orig_goal_len,
 		};
 		loff_t orig_goal_end = extent_logical_end(sbi, &ex);
+		loff_t o_ex_end = extent_logical_end(sbi, &ac->ac_o_ex);
 
-		/* we can't allocate as much as normalizer wants.
-		 * so, found space must get proper lstart
-		 * to cover original request */
+		/*
+		 * We can't allocate as much as normalizer wants, so we try
+		 * to get proper lstart to cover the original request, except
+		 * when the goal doesn't cover the original request as below:
+		 *
+		 * orig_ex:2045/2055(10), isize:8417280 -> normalized:0/2048
+		 * best_ex:0/200(200) -> adjusted: 1848/2048(200)
+		 */
 		BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
 		BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
 
@@ -5188,7 +5194,7 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 		 * 1. Check if best ex can be kept at end of goal (before
 		 *    cr_best_avail trimmed it) and still cover original start
 		 * 2. Else, check if best ex can be kept at start of goal and
-		 *    still cover original start
+		 *    still cover original end
 		 * 3. Else, keep the best ex at start of original request.
 		 */
 		ex.fe_len = ac->ac_b_ex.fe_len;
@@ -5198,7 +5204,7 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 			goto adjust_bex;
 
 		ex.fe_logical = ac->ac_g_ex.fe_logical;
-		if (ac->ac_o_ex.fe_logical < extent_logical_end(sbi, &ex))
+		if (o_ex_end <= extent_logical_end(sbi, &ex))
 			goto adjust_bex;
 
 		ex.fe_logical = ac->ac_o_ex.fe_logical;
@@ -5206,7 +5212,6 @@ ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
 		ac->ac_b_ex.fe_logical = ex.fe_logical;
 
 		BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
-		BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
 		BUG_ON(extent_logical_end(sbi, &ex) > orig_goal_end);
 	}
 




[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]

  Powered by Linux