| Message ID | 20240201141845.1879253-1-libaokun1@huawei.com |
|---|---|
| State | Awaiting Upstream |
| Headers | show |
| Series | [v2] ext4: correct best extent lstart adjustment logic | expand |
Hey Baokun, thanks for the v2. On Thu, Feb 01, 2024 at 10:18:45PM +0800, Baokun Li wrote: > 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@huawei.com > Fixes: 93cdf49f6eca ("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()") > Cc: stable@kernel.org So I'm not sure if this is actually fixing a BUG and if we need to backport this to stable but I guess Ted can take a call on that. Other than that, the patch looks good. Feel free to add: Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Regards, ojaswin > Signed-off-by: yangerkun <yangerkun@huawei.com> > Signed-off-by: Baokun Li <libaokun1@huawei.com>
On Thu 01-02-24 22:18:45, Baokun Li wrote: > 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@huawei.com > Fixes: 93cdf49f6eca ("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()") > Cc: stable@kernel.org > Signed-off-by: yangerkun <yangerkun@huawei.com> > Signed-off-by: Baokun Li <libaokun1@huawei.com> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > V1->V2: > Remove the problematic BUG_ON and add some comments. > > fs/ext4/mballoc.c | 17 +++++++++++------ > 1 file changed, 11 insertions(+), 6 deletions(-) > > diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c > index 1ea6491b6b00..20cad0676aab 100644 > --- a/fs/ext4/mballoc.c > +++ b/fs/ext4/mballoc.c > @@ -5148,10 +5148,16 @@ 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); > > @@ -5163,7 +5169,7 @@ 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; > @@ -5173,7 +5179,7 @@ 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; > @@ -5181,7 +5187,6 @@ 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); > } > > -- > 2.31.1 >
On Thu, 01 Feb 2024 22:18:45 +0800, Baokun Li wrote: > 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) > > [...] Applied, thanks! [1/1] ext4: correct best extent lstart adjustment logic commit: 4fbf8bc733d14bceb16dda46a3f5e19c6a9621c5 Best regards,
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 1ea6491b6b00..20cad0676aab 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -5148,10 +5148,16 @@ 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); @@ -5163,7 +5169,7 @@ 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; @@ -5173,7 +5179,7 @@ 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; @@ -5181,7 +5187,6 @@ 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); }
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@huawei.com Fixes: 93cdf49f6eca ("ext4: Fix best extent lstart adjustment logic in ext4_mb_new_inode_pa()") Cc: stable@kernel.org Signed-off-by: yangerkun <yangerkun@huawei.com> Signed-off-by: Baokun Li <libaokun1@huawei.com> --- V1->V2: Remove the problematic BUG_ON and add some comments. fs/ext4/mballoc.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-)