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Btrfs: tree-checker: detect file extent items with overlapping ranges 

Having file extent items with ranges that overlap each other is a
serious issue that leads to all sorts of corruptions and crashes (like a
BUG_ON() during the course of __btrfs_drop_extents() when it traims file
extent items). Therefore teach the tree checker to detect such cases.
This is motivated by a recently fixed bug (race between ranged full
fsync and writeback or adjacent ranges).

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Filipe Manana 2019-05-06 16:44:12 +01:00 committed by David Sterba
parent 0c713cbab6
commit 4e9845eff5
1 changed files with 45 additions and 4 deletions
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49
fs/btrfs/tree-checker.c
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@ -107,8 +107,26 @@ static void file_extent_err(const struct extent_buffer *eb, int slot,
(!IS_ALIGNED(btrfs_file_extent_##name((leaf), (fi)), (alignment))); \
})
static u64 file_extent_end(struct extent_buffer *leaf,
struct btrfs_key *key,
struct btrfs_file_extent_item *extent)
{
u64 end;
u64 len;
if (btrfs_file_extent_type(leaf, extent) == BTRFS_FILE_EXTENT_INLINE) {
len = btrfs_file_extent_ram_bytes(leaf, extent);
end = ALIGN(key->offset + len, leaf->fs_info->sectorsize);
} else {
len = btrfs_file_extent_num_bytes(leaf, extent);
end = key->offset + len;
}
return end;
}
static int check_extent_data_item(struct extent_buffer *leaf,
struct btrfs_key *key, int slot)
struct btrfs_key *key, int slot,
struct btrfs_key *prev_key)
{
struct btrfs_fs_info *fs_info = leaf->fs_info;
struct btrfs_file_extent_item *fi;
@ -188,6 +206,28 @@ static int check_extent_data_item(struct extent_buffer *leaf,
CHECK_FE_ALIGNED(leaf, slot, fi, offset, sectorsize) ||
CHECK_FE_ALIGNED(leaf, slot, fi, num_bytes, sectorsize))
return -EUCLEAN;
/*
* Check that no two consecutive file extent items, in the same leaf,
* present ranges that overlap each other.
*/
if (slot > 0 &&
prev_key->objectid == key->objectid &&
prev_key->type == BTRFS_EXTENT_DATA_KEY) {
struct btrfs_file_extent_item *prev_fi;
u64 prev_end;
prev_fi = btrfs_item_ptr(leaf, slot - 1,
struct btrfs_file_extent_item);
prev_end = file_extent_end(leaf, prev_key, prev_fi);
if (prev_end > key->offset) {
file_extent_err(leaf, slot - 1,
"file extent end range (%llu) goes beyond start offset (%llu) of the next file extent",
prev_end, key->offset);
return -EUCLEAN;
}
}
return 0;
}
@ -774,14 +814,15 @@ static int check_inode_item(struct extent_buffer *leaf,
* Common point to switch the item-specific validation.
*/
static int check_leaf_item(struct extent_buffer *leaf,
struct btrfs_key *key, int slot)
struct btrfs_key *key, int slot,
struct btrfs_key *prev_key)
{
int ret = 0;
struct btrfs_chunk *chunk;
switch (key->type) {
case BTRFS_EXTENT_DATA_KEY:
ret = check_extent_data_item(leaf, key, slot);
ret = check_extent_data_item(leaf, key, slot, prev_key);
break;
case BTRFS_EXTENT_CSUM_KEY:
ret = check_csum_item(leaf, key, slot);
@ -928,7 +969,7 @@ static int check_leaf(struct extent_buffer *leaf, bool check_item_data)
* Check if the item size and content meet other
* criteria
*/
ret = check_leaf_item(leaf, &key, slot);
ret = check_leaf_item(leaf, &key, slot, &prev_key);
if (ret < 0)
return ret;
}