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authorNaohiro Aota <naohiro.aota@wdc.com>2020-11-10 20:26:12 +0900
committerDavid Sterba <dsterba@suse.com>2020-12-09 19:16:04 +0100
commitf1569c4c10a1e9320b92486d73043c6138859cc5 (patch)
treee27f0aeedd1d03201235235394f5d3210edfe14f
parentd206e9c9c576a0de2e6d1fdf17551e2a548955c0 (diff)
downloadlinux-f1569c4c10a1e9320b92486d73043c6138859cc5.tar.bz2
btrfs: disable fallocate in ZONED mode
fallocate() is implemented by reserving actual extent instead of reservations. This can result in exposing the sequential write constraint of host-managed zoned block devices to the application, which would break the POSIX semantic for the fallocated file. To avoid this, report fallocate() as not supported when in ZONED mode for now. In the future, we may be able to implement "in-memory" fallocate() in ZONED mode by utilizing space_info->bytes_may_use or similar, so this returns EOPNOTSUPP. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/btrfs/file.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index d808928dded6..0e41459b8de6 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -3308,6 +3308,10 @@ static long btrfs_fallocate(struct file *file, int mode,
int blocksize = btrfs_inode_sectorsize(BTRFS_I(inode));
int ret;
+ /* Do not allow fallocate in ZONED mode */
+ if (btrfs_is_zoned(btrfs_sb(inode->i_sb)))
+ return -EOPNOTSUPP;
+
alloc_start = round_down(offset, blocksize);
alloc_end = round_up(offset + len, blocksize);
cur_offset = alloc_start;