diff options
| author | Qu Wenruo <wqu@suse.com> | 2023-02-13 03:37:59 +0300 |
|---|---|---|
| committer | Tom Rini <trini@konsulko.com> | 2023-02-23 21:29:19 +0300 |
| commit | 511a1303c9cf9663c7d4312e3a0693319f41095b (patch) | |
| tree | 21ce986e15db8aeb4ad222d9a5a75fd9ff46952b /fs | |
| parent | 8c39999acb726ef083d3d5de12f20318ee0e5070 (diff) | |
| download | u-boot-511a1303c9cf9663c7d4312e3a0693319f41095b.tar.xz | |
fs: btrfs: limit the mapped length to the original length
[BUG]
There is a bug report that btrfs driver caused hang during file read:
This breaks btrfs on the HiFive Unmatched.
=> pci enum
PCIE-0: Link up (Gen1-x8, Bus0)
=> nvme scan
=> load nvme 0:2 0x8c000000 /boot/dtb/sifive/hifive-unmatched-a00.dtb
[hangs]
[CAUSE]
The reporter provided some debug output:
read_extent_data: cur=615817216, orig_len=16384, cur_len=16384
read_extent_data: btrfs_map_block: cur_len=479944704; ret=0
read_extent_data: ret=0
read_extent_data: cur=615833600, orig_len=4096, cur_len=4096
read_extent_data: btrfs_map_block: cur_len=479928320; ret=0
Note the second and the last line, the @cur_len is 450+MiB, which is
almost a chunk size.
And inside __btrfs_map_block(), we limits the returned value to stripe
length, but that's depending on the chunk type:
if (map->type & (BTRFS_BLOCK_GROUP_RAID0 | BTRFS_BLOCK_GROUP_RAID1 |
BTRFS_BLOCK_GROUP_RAID1C3 | BTRFS_BLOCK_GROUP_RAID1C4 |
BTRFS_BLOCK_GROUP_RAID5 | BTRFS_BLOCK_GROUP_RAID6 |
BTRFS_BLOCK_GROUP_RAID10 |
BTRFS_BLOCK_GROUP_DUP)) {
/* we limit the length of each bio to what fits in a stripe */
*length = min_t(u64, ce->size - offset,
map->stripe_len - stripe_offset);
} else {
*length = ce->size - offset;
}
This means, if the chunk is SINGLE profile, then we don't limit the
returned length at all, and even for other profiles, we can still return
a length much larger than the requested one.
[FIX]
Properly clamp the returned length, preventing it from returning a much
larger range than expected.
Reported-by: Andreas Schwab <schwab@linux-m68k.org>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/volumes.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index 4aaaeab663..7d4095d9ca 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -956,6 +956,7 @@ int __btrfs_map_block(struct btrfs_fs_info *fs_info, int rw, struct btrfs_mapping_tree *map_tree = &fs_info->mapping_tree; struct cache_extent *ce; struct map_lookup *map; + u64 orig_len = *length; u64 offset; u64 stripe_offset; u64 *raid_map = NULL; @@ -1047,6 +1048,7 @@ again: } else { *length = ce->size - offset; } + *length = min_t(u64, *length, orig_len); if (!multi_ret) goto out; |