From 7cf15bcc6afd6f9bbd8caf1c81b5424d1f41190a Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Wed, 22 Nov 2017 17:03:17 +0800 Subject: [PATCH] btrfs-progs: lowmem check: Fix inlined data extent ref lookup When lowmem fsck tries to find backref of a specified file extent, it searches inlined data ref first. However, extent data ref contains both owner root objectid, inode number and calculated offset (file offset - extent offset). The code only checks owner root objectid, not checking inode number nor calculated offset. This makes lowmem mode fail to detect any backref mismatch if there is a inlined data ref with the same owner objectid. Fix it by also checking extent data ref's objectid and offset. Fixes: b0d360b541f0 ("btrfs-progs: check: introduce function to check data backref in extent tree") Reported-by: Chris Murphy Signed-off-by: Qu Wenruo Signed-off-by: David Sterba --- cmds-check.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/cmds-check.c b/cmds-check.c index 03ff89a4..9f9eb504 100644 --- a/cmds-check.c +++ b/cmds-check.c @@ -12005,11 +12005,11 @@ static int check_extent_data_item(struct btrfs_root *root, u64 disk_num_bytes; u64 extent_num_bytes; u64 extent_flags; + u64 offset; u32 item_size; unsigned long end; unsigned long ptr; int type; - u64 ref_root; int found_dbackref = 0; int slot = pathp->slots[0]; int err = 0; @@ -12027,6 +12027,7 @@ static int check_extent_data_item(struct btrfs_root *root, disk_bytenr = btrfs_file_extent_disk_bytenr(eb, fi); disk_num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi); extent_num_bytes = btrfs_file_extent_num_bytes(eb, fi); + offset = btrfs_file_extent_offset(eb, fi); /* Check unaligned disk_num_bytes and num_bytes */ if (!IS_ALIGNED(disk_num_bytes, root->fs_info->sectorsize)) { @@ -12081,6 +12082,11 @@ static int check_extent_data_item(struct btrfs_root *root, strict = should_check_extent_strictly(root, nrefs, -1); while (ptr < end) { + u64 ref_root; + u64 ref_objectid; + u64 ref_offset; + bool match = false; + iref = (struct btrfs_extent_inline_ref *)ptr; type = btrfs_extent_inline_ref_type(leaf, iref); dref = (struct btrfs_extent_data_ref *)(&iref->offset); @@ -12092,9 +12098,15 @@ static int check_extent_data_item(struct btrfs_root *root, } if (type == BTRFS_EXTENT_DATA_REF_KEY) { ref_root = btrfs_extent_data_ref_root(leaf, dref); - if (ref_root == root->objectid) + ref_objectid = btrfs_extent_data_ref_objectid(leaf, dref); + ref_offset = btrfs_extent_data_ref_offset(leaf, dref); + + if (ref_objectid == fi_key.objectid && + ref_offset == fi_key.offset - offset) + match = true; + if (ref_root == root->objectid && match) found_dbackref = 1; - else if (!strict && owner == ref_root) + else if (!strict && owner == ref_root && match) found_dbackref = 1; } else if (type == BTRFS_SHARED_DATA_REF_KEY) { found_dbackref = !check_tree_block_ref(root, NULL,