btrfs: add cancellation points to trim loops

There are reports that system cannot suspend due to running trim because
the task responsible for trimming the device isn't able to finish in
time, especially since we have a free extent discarding phase, which can
trim a lot of unallocated space. There are no limits on the trim size
(unlike the block group part).

Since trime isn't a critical call it can be interrupted at any time,
in such cases we stop the trim, report the amount of discarded bytes and
return an error.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=219180
Link: https://bugzilla.suse.com/show_bug.cgi?id=1229737
CC: stable@vger.kernel.org # 5.15+
Signed-off-by: Luca Stefani <luca.stefani.ge1@gmail.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index ad70548d1f722cb0f64d8d00a0aa7f0ba63a6ce6..d9f511babd89ab5636e4aa1101c5ac7ad9dac1d9 100644 (file)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -1316,6 +1316,11 @@ static int btrfs_issue_discard(struct block_device *bdev, u64 start, u64 len,
                start += bytes_to_discard;
                bytes_left -= bytes_to_discard;
                *discarded_bytes += bytes_to_discard;
+
+               if (btrfs_trim_interrupted()) {
+                       ret = -ERESTARTSYS;
+                       break;
+               }
        }
 
        return ret;
@@ -6470,7 +6475,7 @@ static int btrfs_trim_free_extents(struct btrfs_device *device, u64 *trimmed)
                start += len;
                *trimmed += bytes;
 
-               if (fatal_signal_pending(current)) {
+               if (btrfs_trim_interrupted()) {
                        ret = -ERESTARTSYS;
                        break;
                }

diff --git a/fs/btrfs/free-space-cache.c b/fs/btrfs/free-space-cache.c
index eaa1dbd313528cf33ea44f7c2bb5cde0701d70ca..f4bcb25306606ab6020619797c0f763bb3771a89 100644 (file)
--- a/fs/btrfs/free-space-cache.c
+++ b/fs/btrfs/free-space-cache.c
@@ -3809,7 +3809,7 @@ next:
                if (async && *total_trimmed)
                        break;
 
-               if (fatal_signal_pending(current)) {
+               if (btrfs_trim_interrupted()) {
                        ret = -ERESTARTSYS;
                        break;
                }
@@ -4000,7 +4000,7 @@ next:
                }
                block_group->discard_cursor = start;
 
-               if (fatal_signal_pending(current)) {
+               if (btrfs_trim_interrupted()) {
                        if (start != offset)
                                reset_trimming_bitmap(ctl, offset);
                        ret = -ERESTARTSYS;

diff --git a/fs/btrfs/free-space-cache.h b/fs/btrfs/free-space-cache.h
index 83774bfd7b3bb09119d0258900b0514307e5536b..9f1dbfdee8cabfef7e6aa87928c2c3ccdcea950f 100644 (file)
--- a/fs/btrfs/free-space-cache.h
+++ b/fs/btrfs/free-space-cache.h
@@ -10,6 +10,7 @@
 #include <linux/list.h>
 #include <linux/spinlock.h>
 #include <linux/mutex.h>
+#include <linux/freezer.h>
 #include "fs.h"
 
 struct inode;
@@ -56,6 +57,11 @@ static inline bool btrfs_free_space_trimming_bitmap(
        return (info->trim_state == BTRFS_TRIM_STATE_TRIMMING);
 }
 
+static inline bool btrfs_trim_interrupted(void)
+{
+       return fatal_signal_pending(current) || freezing(current);
+}
+
 /*
  * Deltas are an effective way to populate global statistics.  Give macro names
  * to make it clear what we're doing.  An example is discard_extents in