[Cluster-devel] [PATCH] gfs2: Fix loop in gfs2_rbm_find (2)

[Cluster-devel] [PATCH] gfs2: Fix loop in gfs2_rbm_find (2)

[Andreas Gruenbacher]

The fix from commit 2d29f6b96d8f introduced an unexpected performance
regression when allocating blocks.  Fix by rewriting the overly
complicated wrap-around logic in gfs2_rbm_find in a more reasonable way.
Discovered and verified with iozone.

Fixes: 2d29f6b96d8f ("gfs2: Fix loop in gfs2_rbm_find")
Cc: stable at vger.kernel.org # v3.13+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/gfs2/rgrp.c | 40 +++++++++++++---------------------------
 1 file changed, 13 insertions(+), 27 deletions(-)

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 831d7cb5a49c4..3f16411d885d9 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -1730,25 +1730,15 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
 			 const struct gfs2_inode *ip, bool nowrap)
 {
 	struct buffer_head *bh;
-	int initial_bii;
-	u32 initial_offset;
 	int first_bii = rbm->bii;
 	u32 first_offset = rbm->offset;
 	u32 offset;
 	u8 *buffer;
-	int n = 0;
-	int iters = rbm->rgd->rd_length;
+	bool wrapped = false;
 	int ret;
 	struct gfs2_bitmap *bi;
 	struct gfs2_extent maxext = { .rbm.rgd = rbm->rgd, };
 
-	/* If we are not starting at the beginning of a bitmap, then we
-	 * need to add one to the bitmap count to ensure that we search
-	 * the starting bitmap twice.
-	 */
-	if (rbm->offset != 0)
-		iters++;
-
 	while(1) {
 		bi = rbm_bi(rbm);
 		if ((ip == NULL || !gfs2_rs_active(&ip->i_res)) &&
@@ -1761,47 +1751,43 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
 		WARN_ON(!buffer_uptodate(bh));
 		if (state != GFS2_BLKST_UNLINKED && bi->bi_clone)
 			buffer = bi->bi_clone + bi->bi_offset;
-		initial_offset = rbm->offset;
 		offset = gfs2_bitfit(buffer, bi->bi_bytes, rbm->offset, state);
-		if (offset == BFITNOENT)
-			goto bitmap_full;
+		if (offset == BFITNOENT) {
+			if (state == GFS2_BLKST_FREE && rbm->offset == 0)
+				set_bit(GBF_FULL, &bi->bi_flags);
+			goto next_bitmap;
+		}
 		rbm->offset = offset;
 		if (ip == NULL)
 			return 0;
 
-		initial_bii = rbm->bii;
 		ret = gfs2_reservation_check_and_update(rbm, ip,
 							minext ? *minext : 0,
 							&maxext);
 		if (ret == 0)
 			return 0;
-		if (ret > 0) {
-			n += (rbm->bii - initial_bii);
+		if (ret > 0)
 			goto next_iter;
-		}
 		if (ret == -E2BIG) {
-			n += rbm->bii - initial_bii;
 			rbm->bii = 0;
 			rbm->offset = 0;
 			goto res_covered_end_of_rgrp;
 		}
 		return ret;
 
-bitmap_full:	/* Mark bitmap as full and fall through */
-		if ((state == GFS2_BLKST_FREE) && initial_offset == 0)
-			set_bit(GBF_FULL, &bi->bi_flags);
-
 next_bitmap:	/* Find next bitmap in the rgrp */
 		rbm->offset = 0;
 		rbm->bii++;
 		if (rbm->bii == rbm->rgd->rd_length)
 			rbm->bii = 0;
 res_covered_end_of_rgrp:
-		if ((rbm->bii == 0) && nowrap)
-			break;
-		n++;
+		if (rbm->bii == 0) {
+			if (nowrap)
+				break;
+			wrapped = true;
+		}
 next_iter:
-		if (n >= iters)
+		if (wrapped && rbm->bii > first_bii)
 			break;
 	}
 
-- 
2.20.1

[Cluster-devel] [PATCH] gfs2: Fix loop in gfs2_rbm_find (2)

[Bob Peterson]

----- Original Message -----
> The fix from commit 2d29f6b96d8f introduced an unexpected performance
> regression when allocating blocks.  Fix by rewriting the overly
> complicated wrap-around logic in gfs2_rbm_find in a more reasonable way.
> Discovered and verified with iozone.
> 
> Fixes: 2d29f6b96d8f ("gfs2: Fix loop in gfs2_rbm_find")
> Cc: stable at vger.kernel.org # v3.13+
> Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
> ---
>  fs/gfs2/rgrp.c | 40 +++++++++++++---------------------------
>  1 file changed, 13 insertions(+), 27 deletions(-)
> 
> diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
> index 831d7cb5a49c4..3f16411d885d9 100644
> --- a/fs/gfs2/rgrp.c
> +++ b/fs/gfs2/rgrp.c
> @@ -1730,25 +1730,15 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8
> state, u32 *minext,
>  			 const struct gfs2_inode *ip, bool nowrap)
>  {
>  	struct buffer_head *bh;
> -	int initial_bii;
> -	u32 initial_offset;
>  	int first_bii = rbm->bii;
>  	u32 first_offset = rbm->offset;
>  	u32 offset;
>  	u8 *buffer;
> -	int n = 0;
> -	int iters = rbm->rgd->rd_length;
> +	bool wrapped = false;
>  	int ret;
>  	struct gfs2_bitmap *bi;
>  	struct gfs2_extent maxext = { .rbm.rgd = rbm->rgd, };
>  
> -	/* If we are not starting at the beginning of a bitmap, then we
> -	 * need to add one to the bitmap count to ensure that we search
> -	 * the starting bitmap twice.
> -	 */
> -	if (rbm->offset != 0)
> -		iters++;
> -
>  	while(1) {
>  		bi = rbm_bi(rbm);
>  		if ((ip == NULL || !gfs2_rs_active(&ip->i_res)) &&
> @@ -1761,47 +1751,43 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8
> state, u32 *minext,
>  		WARN_ON(!buffer_uptodate(bh));
>  		if (state != GFS2_BLKST_UNLINKED && bi->bi_clone)
>  			buffer = bi->bi_clone + bi->bi_offset;
> -		initial_offset = rbm->offset;
>  		offset = gfs2_bitfit(buffer, bi->bi_bytes, rbm->offset, state);
> -		if (offset == BFITNOENT)
> -			goto bitmap_full;
> +		if (offset == BFITNOENT) {
> +			if (state == GFS2_BLKST_FREE && rbm->offset == 0)
> +				set_bit(GBF_FULL, &bi->bi_flags);
> +			goto next_bitmap;
> +		}
>  		rbm->offset = offset;
>  		if (ip == NULL)
>  			return 0;
>  
> -		initial_bii = rbm->bii;
>  		ret = gfs2_reservation_check_and_update(rbm, ip,
>  							minext ? *minext : 0,
>  							&maxext);
>  		if (ret == 0)
>  			return 0;
> -		if (ret > 0) {
> -			n += (rbm->bii - initial_bii);
> +		if (ret > 0)
>  			goto next_iter;
> -		}
>  		if (ret == -E2BIG) {
> -			n += rbm->bii - initial_bii;
>  			rbm->bii = 0;
>  			rbm->offset = 0;
>  			goto res_covered_end_of_rgrp;
>  		}
>  		return ret;
>  
> -bitmap_full:	/* Mark bitmap as full and fall through */
> -		if ((state == GFS2_BLKST_FREE) && initial_offset == 0)
> -			set_bit(GBF_FULL, &bi->bi_flags);
> -
>  next_bitmap:	/* Find next bitmap in the rgrp */
>  		rbm->offset = 0;
>  		rbm->bii++;
>  		if (rbm->bii == rbm->rgd->rd_length)
>  			rbm->bii = 0;
>  res_covered_end_of_rgrp:
> -		if ((rbm->bii == 0) && nowrap)
> -			break;
> -		n++;
> +		if (rbm->bii == 0) {
> +			if (nowrap)
> +				break;
> +			wrapped = true;
> +		}
>  next_iter:
> -		if (n >= iters)
> +		if (wrapped && rbm->bii > first_bii)
>  			break;
>  	}
>  
> --
> 2.20.1

Hi,

I think you're on the right track here, and I definitely like most of your
improvements, but I'm concerned about one thing.

The reason we currently do (rd_length + 1) iterations is, for example, cases
where space is really tight and the starting point of the search comes after the
last free block.

So simplifying the test down to a tiny file system where there is only one
rgrp, which contains the only bitmap. Assuming block size 4K, minus the rgrp
header, you've got 0xf80 (3968) bytes possible, or 1984 blocks possible.

Let's say you have two processes, A and B. 
Let's say A wants to create a dinode, and its "hint" says to start at the (only)
bitmap block 1500. But process B already has the rgrp locked because he's freeing
a dinode at block 1000, so he marks block 1000 free and releases the lock.
Now process A starts searching the bitmap at offset 1500 until the end.
The only free block is 1000 (because of process B's free), so A's bitmap search
reaches the end of the bitmap and gets BFITNOENT.

With this new patch, it will just go back next_bitmap, but there are no more
bitmaps. It sets wrap, but since we're at the end, it returns -ENOSPC, when,
in fact, there is a free block, no?

That's why we coded it the way we did: With today's algorithm, it would reach
the end of the rgrp, wrap to the beginning again, and find free block 1000.

I know this scenario may seem absurd. My concern is not whether this particular
scenario is broken with the patch, but more that the algorithm may cause:

(a) more file system fragmentation
(b) more file fragmentation
(c) improperly reporting of -ENOSPC
(d) or something else.

Before we push this upstream, we should probably run a file system aging test,
like sas calibration without unmounts, and compare filefrag results with older
kernels that don't have 2d29f6b96d8f. And we should do it with very little free
space after, say, 13 iterations. IOW, so it hits free space limitations for
many different rgrps.

Regards,

Bob Peterson
Red Hat File Systems

[Cluster-devel] [PATCH] gfs2: Fix loop in gfs2_rbm_find (2)

[Bob Peterson]

----- Original Message -----
> ----- Original Message -----
> > The fix from commit 2d29f6b96d8f introduced an unexpected performance
> > regression when allocating blocks.  Fix by rewriting the overly
> > complicated wrap-around logic in gfs2_rbm_find in a more reasonable way.
> > Discovered and verified with iozone.
> > 
> > Fixes: 2d29f6b96d8f ("gfs2: Fix loop in gfs2_rbm_find")
> > Cc: stable at vger.kernel.org # v3.13+
> > Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
(snip)
> With this new patch, it will just go back next_bitmap, but there are no more
> bitmaps. It sets wrap, but since we're at the end, it returns -ENOSPC, when,
> in fact, there is a free block, no?

On closer inspection, the patch looks okay to me. 
I still want to test it before we push it.

Bob Peterson

[Cluster-devel] [PATCH] gfs2: Fix loop in gfs2_rbm_find (2)

[Sasha Levin]

Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag,
fixing commit: 2d29f6b96d8f gfs2: Fix loop in gfs2_rbm_find.

The bot has tested the following trees: v4.20.5, v4.19.18, v4.14.96, v4.9.153, v4.4.172, v3.18.133.

v4.20.5: Build OK!
v4.19.18: Failed to apply! Possible dependencies:
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")

v4.14.96: Failed to apply! Possible dependencies:
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too long")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")

v4.9.153: Failed to apply! Possible dependencies:
    0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws occur")
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
    dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too long")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")
    ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")

v4.4.172: Failed to apply! Possible dependencies:
    0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws occur")
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    3e11e5304150 ("GFS2: ignore unlock failures after withdraw")
    471f3db2786b ("gfs2: change gfs2 readdir cookie")
    9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
    dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too long")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")
    ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")

v3.18.133: Failed to apply! Possible dependencies:
    0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws occur")
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    2e60d7683c8d ("GFS2: update freeze code to use freeze/thaw_super on all nodes")
    3cdcf63ed2d1 ("GFS2: use kvfree() instead of open-coding it")
    3e11e5304150 ("GFS2: ignore unlock failures after withdraw")
    471f3db2786b ("gfs2: change gfs2 readdir cookie")
    9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
    a3e3213676d8 ("gfs2: fix shadow warning in gfs2_rbm_find()")
    dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too long")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")
    ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")


How should we proceed with this patch?

--
Thanks,
Sasha

[Cluster-devel] [PATCH] gfs2: Fix loop in gfs2_rbm_find (2)

[Bob Peterson]

----- Original Message -----
> Hi,
> 
> [This is an automated email]
> 
> This commit has been processed because it contains a "Fixes:" tag,
> fixing commit: 2d29f6b96d8f gfs2: Fix loop in gfs2_rbm_find.
> 
> The bot has tested the following trees: v4.20.5, v4.19.18, v4.14.96,
> v4.9.153, v4.4.172, v3.18.133.
> 
> v4.20.5: Build OK!
> v4.19.18: Failed to apply! Possible dependencies:
>     281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
>     e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we
>     can")
> 
> v4.14.96: Failed to apply! Possible dependencies:
>     281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
>     dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too
>     long")
>     e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we
>     can")
> 
> v4.9.153: Failed to apply! Possible dependencies:
>     0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws
>     occur")
>     281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
>     9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
>     dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too
>     long")
>     e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we
>     can")
>     ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")
> 
> v4.4.172: Failed to apply! Possible dependencies:
>     0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws
>     occur")
>     281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
>     3e11e5304150 ("GFS2: ignore unlock failures after withdraw")
>     471f3db2786b ("gfs2: change gfs2 readdir cookie")
>     9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
>     dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too
>     long")
>     e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we
>     can")
>     ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")
> 
> v3.18.133: Failed to apply! Possible dependencies:
>     0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws
>     occur")
>     281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
>     2e60d7683c8d ("GFS2: update freeze code to use freeze/thaw_super on all
>     nodes")
>     3cdcf63ed2d1 ("GFS2: use kvfree() instead of open-coding it")
>     3e11e5304150 ("GFS2: ignore unlock failures after withdraw")
>     471f3db2786b ("gfs2: change gfs2 readdir cookie")
>     9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
>     a3e3213676d8 ("gfs2: fix shadow warning in gfs2_rbm_find()")
>     dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too
>     long")
>     e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we
>     can")
>     ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")
> 
> 
> How should we proceed with this patch?
> 
> --
> Thanks,
> Sasha

Hi Sasha,

We have found problems with the "gfs2: Fix loop in gfs2_rbm_find (2)" patch,
so for now we would like to revert the patch it's trying to fix, which is
"gfs2: Fix loop in gfs2_rbm_find" (the original).

Andreas Gruenbacher just sent a revert request for the broken patch to Linus,
so we should just delete "gfs2: Fix loop in gfs2_rbm_find (2)" until we can
get a proper replacement and test it thoroughly.

Regards,

Bob Peterson

[Cluster-devel] [PATCH] gfs2: Fix loop in gfs2_rbm_find (2)

[Andreas Gruenbacher]

This is an updated version of the patch previously posted on January 24.

Changes since then:

 - The previous version didn't take filesystems with a single bitmap
   block per filesystem into account, and could still loop endlessly
   in that case.

 - When starting a scan at the beginning of a bitmap block and we wrap
   around, there is no need to rescan that bitmap block again.  This
   revised version takes that into account as well.

 - At the end of gfs2_rbm_find, we update rd_extfail_pt when the scan
   has started at the beginning of the resource group.  However, we
   should update rd_extfail_pt whenever we have scanned the entire
   resource group, including when we have wrapped around.

--

The fix from commit 2d29f6b96d8f introduced an unexpected performance
regression when allocating blocks.  Fix by rewriting the overly complicated
wrap-around logic in gfs2_rbm_find.  Discovered and verified with iozone.

Fixes: 2d29f6b96d8f ("gfs2: Fix loop in gfs2_rbm_find")
Cc: stable at vger.kernel.org # v3.13+
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
---
 fs/gfs2/rgrp.c | 54 +++++++++++++++++++++++---------------------------
 1 file changed, 25 insertions(+), 29 deletions(-)

diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 831d7cb5a49c4..52a4f340a8672 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -1729,25 +1729,22 @@ static int gfs2_reservation_check_and_update(struct gfs2_rbm *rbm,
 static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
 			 const struct gfs2_inode *ip, bool nowrap)
 {
+	bool scan_from_start = rbm->bii == 0 && rbm->offset == 0;
 	struct buffer_head *bh;
-	int initial_bii;
-	u32 initial_offset;
-	int first_bii = rbm->bii;
-	u32 first_offset = rbm->offset;
+	int last_bii;
 	u32 offset;
 	u8 *buffer;
-	int n = 0;
-	int iters = rbm->rgd->rd_length;
+	bool wrapped = false;
 	int ret;
 	struct gfs2_bitmap *bi;
 	struct gfs2_extent maxext = { .rbm.rgd = rbm->rgd, };
 
-	/* If we are not starting at the beginning of a bitmap, then we
-	 * need to add one to the bitmap count to ensure that we search
-	 * the starting bitmap twice.
+	/*
+	 * Determine the last bitmap to search.  If we're not starting at the
+	 * beginning of a bitmap, we need to search that bitmap twice to scan
+	 * the entire resource group.
 	 */
-	if (rbm->offset != 0)
-		iters++;
+	last_bii = rbm->bii - (rbm->offset == 0);
 
 	while(1) {
 		bi = rbm_bi(rbm);
@@ -1761,47 +1758,46 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
 		WARN_ON(!buffer_uptodate(bh));
 		if (state != GFS2_BLKST_UNLINKED && bi->bi_clone)
 			buffer = bi->bi_clone + bi->bi_offset;
-		initial_offset = rbm->offset;
 		offset = gfs2_bitfit(buffer, bi->bi_bytes, rbm->offset, state);
-		if (offset == BFITNOENT)
-			goto bitmap_full;
+		if (offset == BFITNOENT) {
+			if (state == GFS2_BLKST_FREE && rbm->offset == 0)
+				set_bit(GBF_FULL, &bi->bi_flags);
+			goto next_bitmap;
+		}
 		rbm->offset = offset;
 		if (ip == NULL)
 			return 0;
 
-		initial_bii = rbm->bii;
 		ret = gfs2_reservation_check_and_update(rbm, ip,
 							minext ? *minext : 0,
 							&maxext);
 		if (ret == 0)
 			return 0;
-		if (ret > 0) {
-			n += (rbm->bii - initial_bii);
+		if (ret > 0)
 			goto next_iter;
-		}
 		if (ret == -E2BIG) {
-			n += rbm->bii - initial_bii;
 			rbm->bii = 0;
 			rbm->offset = 0;
 			goto res_covered_end_of_rgrp;
 		}
 		return ret;
 
-bitmap_full:	/* Mark bitmap as full and fall through */
-		if ((state == GFS2_BLKST_FREE) && initial_offset == 0)
-			set_bit(GBF_FULL, &bi->bi_flags);
-
 next_bitmap:	/* Find next bitmap in the rgrp */
 		rbm->offset = 0;
 		rbm->bii++;
 		if (rbm->bii == rbm->rgd->rd_length)
 			rbm->bii = 0;
 res_covered_end_of_rgrp:
-		if ((rbm->bii == 0) && nowrap)
-			break;
-		n++;
+		if (rbm->bii == 0) {
+			if (wrapped)
+				break;
+			wrapped = true;
+			if (nowrap)
+				break;
+		}
 next_iter:
-		if (n >= iters)
+		/* Have we scanned the entire resource group? */
+		if (wrapped && rbm->bii > last_bii)
 			break;
 	}
 
@@ -1811,8 +1807,8 @@ static int gfs2_rbm_find(struct gfs2_rbm *rbm, u8 state, u32 *minext,
 	/* If the extent was too small, and it's smaller than the smallest
 	   to have failed before, remember for future reference that it's
 	   useless to search this rgrp again for this amount or more. */
-	if ((first_offset == 0) && (first_bii == 0) &&
-	    (*minext < rbm->rgd->rd_extfail_pt))
+	if (wrapped && (scan_from_start || rbm->bii > last_bii) &&
+	    *minext < rbm->rgd->rd_extfail_pt)
 		rbm->rgd->rd_extfail_pt = *minext;
 
 	/* If the maximum extent we found is big enough to fulfill the
-- 
2.20.1

[Cluster-devel] [PATCH] gfs2: Fix loop in gfs2_rbm_find (2)

[Sasha Levin]

Hi,

[This is an automated email]

This commit has been processed because it contains a "Fixes:" tag,
fixing commit: 2d29f6b96d8f gfs2: Fix loop in gfs2_rbm_find.

The bot has tested the following trees: v4.20.6, v4.19.19, v4.14.97, v4.9.154, v4.4.172, v3.18.133.

v4.20.6: Build OK!
v4.19.19: Failed to apply! Possible dependencies:
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")

v4.14.97: Failed to apply! Possible dependencies:
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too long")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")

v4.9.154: Failed to apply! Possible dependencies:
    0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws occur")
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
    dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too long")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")
    ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")

v4.4.172: Failed to apply! Possible dependencies:
    0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws occur")
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    3e11e5304150 ("GFS2: ignore unlock failures after withdraw")
    471f3db2786b ("gfs2: change gfs2 readdir cookie")
    9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
    dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too long")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")
    ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")

v3.18.133: Failed to apply! Possible dependencies:
    0d1c7ae9d849 ("GFS2: Prevent BUG from occurring when normal Withdraws occur")
    281b4952d185 ("gfs2: Rename bitmap.bi_{len => bytes}")
    2e60d7683c8d ("GFS2: update freeze code to use freeze/thaw_super on all nodes")
    3cdcf63ed2d1 ("GFS2: use kvfree() instead of open-coding it")
    3e11e5304150 ("GFS2: ignore unlock failures after withdraw")
    471f3db2786b ("gfs2: change gfs2 readdir cookie")
    9862ca056e65 ("GFS2: Switch tr_touched to flag in transaction")
    a3e3213676d8 ("gfs2: fix shadow warning in gfs2_rbm_find()")
    dc8fbb03dcd6 ("GFS2: gfs2_free_extlen can return an extent that is too long")
    e54c78a27fcd ("gfs2: Use fs_* functions instead of pr_* function where we can")
    ed17545d01e4 ("GFS2: Allow glocks to be unlocked after withdraw")


How should we proceed with this patch?

--
Thanks,
Sasha