summaryrefslogtreecommitdiff
path: root/fs
diff options
context:
space:
mode:
authorJosef Bacik <josef@toxicpanda.com>2020-02-13 10:47:31 -0500
committerDavid Sterba <dsterba@suse.com>2020-02-19 00:39:08 +0100
commitb778cf962d71a0e737923d55d0432f3bd287258e (patch)
tree9bea99b4da9b5c84421d23bdeaaf5deee5e149fa /fs
parentbd727173e4432fe6cb70ba108dc1f3602c5409d7 (diff)
btrfs: fix bytes_may_use underflow in prealloc error condtition
I hit the following warning while running my error injection stress testing: WARNING: CPU: 3 PID: 1453 at fs/btrfs/space-info.h:108 btrfs_free_reserved_data_space_noquota+0xfd/0x160 [btrfs] RIP: 0010:btrfs_free_reserved_data_space_noquota+0xfd/0x160 [btrfs] Call Trace: btrfs_free_reserved_data_space+0x4f/0x70 [btrfs] __btrfs_prealloc_file_range+0x378/0x470 [btrfs] elfcorehdr_read+0x40/0x40 ? elfcorehdr_read+0x40/0x40 ? btrfs_commit_transaction+0xca/0xa50 [btrfs] ? dput+0xb4/0x2a0 ? btrfs_log_dentry_safe+0x55/0x70 [btrfs] ? btrfs_sync_file+0x30e/0x420 [btrfs] ? do_fsync+0x38/0x70 ? __x64_sys_fdatasync+0x13/0x20 ? do_syscall_64+0x5b/0x1b0 ? entry_SYSCALL_64_after_hwframe+0x44/0xa9 This happens if we fail to insert our reserved file extent. At this point we've already converted our reservation from ->bytes_may_use to ->bytes_reserved. However once we break we will attempt to free everything from [cur_offset, end] from ->bytes_may_use, but our extent reservation will overlap part of this. Fix this problem by adding ins.offset (our extent allocation size) to cur_offset so we remove the actual remaining part from ->bytes_may_use. I validated this fix using my inject-error.py script python inject-error.py -o should_fail_bio -t cache_save_setup -t \ __btrfs_prealloc_file_range \ -t insert_reserved_file_extent.constprop.0 \ -r "-5" ./run-fsstress.sh where run-fsstress.sh simply mounts and runs fsstress on a disk. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/btrfs/inode.c16
1 files changed, 13 insertions, 3 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 36deef69f847..4f47ba652b31 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -9824,6 +9824,7 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
struct btrfs_root *root = BTRFS_I(inode)->root;
struct btrfs_key ins;
u64 cur_offset = start;
+ u64 clear_offset = start;
u64 i_size;
u64 cur_bytes;
u64 last_alloc = (u64)-1;
@@ -9858,6 +9859,15 @@ static int __btrfs_prealloc_file_range(struct inode *inode, int mode,
btrfs_end_transaction(trans);
break;
}
+
+ /*
+ * We've reserved this space, and thus converted it from
+ * ->bytes_may_use to ->bytes_reserved. Any error that happens
+ * from here on out we will only need to clear our reservation
+ * for the remaining unreserved area, so advance our
+ * clear_offset by our extent size.
+ */
+ clear_offset += ins.offset;
btrfs_dec_block_group_reservations(fs_info, ins.objectid);
last_alloc = ins.offset;
@@ -9937,9 +9947,9 @@ next:
if (own_trans)
btrfs_end_transaction(trans);
}
- if (cur_offset < end)
- btrfs_free_reserved_data_space(inode, NULL, cur_offset,
- end - cur_offset + 1);
+ if (clear_offset < end)
+ btrfs_free_reserved_data_space(inode, NULL, clear_offset,
+ end - clear_offset + 1);
return ret;
}