ext4: avoid trim error on fs with small groups

[ Upstream commit 173b6e383d2a204c9921ffc1eca3b87aa2106c33 ]

A user reported FITRIM ioctl failing for him on ext4 on some devices
without apparent reason.  After some debugging we've found out that
these devices (being LVM volumes) report rather large discard
granularity of 42MB and the filesystem had 1k blocksize and thus group
size of 8MB. Because ext4 FITRIM implementation puts discard
granularity into minlen, ext4_trim_fs() declared the trim request as
invalid. However just silently doing nothing seems to be a more
appropriate reaction to such combination of parameters since user did
not specify anything wrong.

CC: Lukas Czerner <lczerner@redhat.com>
Fixes: 5c2ed62fd447 ("ext4: Adjust minlen with discard_granularity in the FITRIM ioctl")
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20211112152202.26614-1-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index 84f8d07302efa8db66587b1ad603ac5f81a0a4f9..a224d6efb5a6de8a5a2cbe8c386bc2c06a33c1da 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -610,8 +610,6 @@ resizefs_out:
                    sizeof(range)))
                        return -EFAULT;
 
-               range.minlen = max((unsigned int)range.minlen,
-                                  q->limits.discard_granularity);
                ret = ext4_trim_fs(sb, &range);
                if (ret < 0)
                        return ret;

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index ac87f7e5d6a4ffef9d84d7dfb6b908c0c11028f1..c7be47ed71144d3138f9e8c668f6a51b8d4fddb6 100644 (file)
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -5223,6 +5223,7 @@ out:
  */
 int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
 {
+       struct request_queue *q = bdev_get_queue(sb->s_bdev);
        struct ext4_group_info *grp;
        ext4_group_t group, first_group, last_group;
        ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
@@ -5241,6 +5242,13 @@ int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
            start >= max_blks ||
            range->len < sb->s_blocksize)
                return -EINVAL;
+       /* No point to try to trim less than discard granularity */
+       if (range->minlen < q->limits.discard_granularity) {
+               minlen = EXT4_NUM_B2C(EXT4_SB(sb),
+                       q->limits.discard_granularity >> sb->s_blocksize_bits);
+               if (minlen > EXT4_CLUSTERS_PER_GROUP(sb))
+                       goto out;
+       }
        if (end >= max_blks)
                end = max_blks - 1;
        if (end <= first_data_blk)