So we don't check the validity of records as we walk the btree. When
there are corrupt records in the free space btree (e.g. zero
startblock/length or beyond EOAG) we just blindly use it and things
go bad from there. That leads to assert failures on debug kernels
like this:
XFS: Assertion failed: fs_is_ok, file: fs/xfs/libxfs/xfs_alloc.c, line: 450
....
Call Trace:
xfs_alloc_fixup_trees+0x368/0x5c0
xfs_alloc_ag_vextent_near+0x79a/0xe20
xfs_alloc_ag_vextent+0x1d3/0x330
xfs_alloc_vextent+0x5e9/0x870
Or crashes like this:
XFS (loop0): xfs_buf_find: daddr 0x7fb28 out of range, EOFS 0x8000
.....
BUG: unable to handle kernel NULL pointer dereference at 00000000000000c8
....
Call Trace:
xfs_bmap_add_extent_hole_real+0x67d/0x930
xfs_bmapi_write+0x934/0xc90
xfs_da_grow_inode_int+0x27e/0x2f0
xfs_dir2_grow_inode+0x55/0x130
xfs_dir2_sf_to_block+0x94/0x5d0
xfs_dir2_sf_addname+0xd0/0x590
xfs_dir_createname+0x168/0x1a0
xfs_rename+0x658/0x9b0
By checking that free space records pulled from the trees are
within the valid range, we catch many of these corruptions before
they can do damage.
This is a generic btree record checking deficiency. We need to
validate the records we fetch from all the different btrees before
we use them to catch corruptions like this.
This patch results in a corrupt record emitting an error message and
returning -EFSCORRUPTED, and the higher layers catch that and abort:
XFS (loop0): Size Freespace BTree record corruption in AG 0 detected!
XFS (loop0): start block 0x0 block count 0x0
XFS (loop0): Internal error xfs_trans_cancel at line 1012 of file fs/xfs/xfs_trans.c. Caller xfs_create+0x42a/0x670
.....
Call Trace:
dump_stack+0x85/0xcb
xfs_trans_cancel+0x19f/0x1c0
xfs_create+0x42a/0x670
xfs_generic_create+0x1f6/0x2c0
vfs_create+0xf9/0x180
do_mknodat+0x1f9/0x210
do_syscall_64+0x5a/0x180
entry_SYSCALL_64_after_hwframe+0x49/0xbe
.....
XFS (loop0): xfs_do_force_shutdown(0x8) called from line 1013 of file fs/xfs/xfs_trans.c. Return address = ffffffff81500868
XFS (loop0): Corruption of in-memory data detected. Shutting down filesystem
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
9e6c08d4a8