kernel/linux.git/fs/xfs/scrub, branch linux-5.3.y

xfs: Fix possible null-pointer dereferences in xchk_da_btree_block_check_sibling()

2019-07-30T18:28:20+00:00

In xchk_da_btree_block_check_sibling(), there is an if statement on line 274 to check whether ds->state->altpath.blk[level].bp is NULL: if (ds->state->altpath.blk[level].bp) When ds->state->altpath.blk[level].bp is NULL, it is used on line 281: xfs_trans_brelse(..., ds->state->altpath.blk[level].bp); struct xfs_buf_log_item *bip = bp->b_log_item; ASSERT(bp->b_transp == tp); Thus, possible null-pointer dereferences may occur. To fix these bugs, ds->state->altpath.blk[level].bp is checked before being used. These bugs are found by a static analysis tool STCheck written by us. Signed-off-by: Jia-Ju Bai Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

xfs: online scrub needn't bother zeroing its temporary buffer

2019-07-05T17:29:56+00:00

The xattr scrubber functions use the temporary memory buffer either for storing bitmaps or for testing if attribute value extraction works. The bitmap code always zeroes what it needs and the value extraction sets the buffer contents, so it's not necessary to waste CPU time zeroing on allocation. Note that while we never read the contents that the attr value extraction function sets, we do need to call it to check the remote attribute header and CRCs to check for corruption. A flame graph analysis showed that we were spending 7% of a xfs_scrub run (the whole program, not just the attr scrubber itself) allocating and zeroing 64k segments needlessly. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster

xfs: only allocate memory for scrubbing attributes when we need it

2019-07-05T17:29:56+00:00

In examining a flame graph of time spent running xfs_scrub on various filesystems, I noticed that we spent nearly 7% of the total runtime on allocating a zeroed 65k buffer for every SCRUB_TYPE_XATTR invocation. We do this even if none of the attribute values were anywhere near 64k in size, even if there were no attribute blocks to check space on, and even if it just turns out there are no attributes at all. Therefore, rearrange the xattr buffer setup code to support reallocating with a bigger buffer and redistribute the callers of that function so that we only allocate memory just prior to needing it, and only allocate as much as we need. If we can't get memory with the ILOCK held we'll bail out with EDEADLOCK which will allocate the maximum memory. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster

xfs: refactor attr scrub memory allocation function

2019-07-05T17:29:55+00:00

Move the code that allocates memory buffers for the extended attribute scrub code into a separate function so we can reduce memory allocations in the next patch. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster

xfs: refactor extended attribute buffer pointer functions

2019-07-05T17:29:55+00:00

Replace the open-coded attribute buffer pointer calculations with helper functions to make it more obvious what we're doing with our freeform memory allocation w.r.t. either storing xattr values or computing btree block free space. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster

xfs: attribute scrub should use seen_enough to pass error values

2019-07-05T17:29:54+00:00

When we're iterating all the attributes using the built-in xattr iterator, we can use the seen_enough variable to pass error codes back to the main scrub function instead of flattening them into 0/1. This will be used in a more exciting fashion in upcoming patches. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster

xfs: create iterator error codes

2019-07-02T16:40:05+00:00

Currently, xfs doesn't have generic error codes defined for "stop iterating"; we just reuse the XFS_BTREE_QUERY_* return values. This looks a little weird if we're not actually iterating a btree index. Before we start adding more iterators, we should create general XFS_ITER_{CONTINUE,ABORT} return values and define the XFS_BTREE_QUERY_* ones from that. Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster

xfs: remove unused header files

2019-06-29T02:30:43+00:00

There are many, many xfs header files which are included but unneeded (or included twice) in the xfs code, so remove them. nb: xfs_linux.h includes about 9 headers for everyone, so those explicit includes get removed by this. I'm not sure what the preference is, but if we wanted explicit includes everywhere, a followup patch could remove those xfs_*.h includes from xfs_linux.h and move them into the files that need them. Or it could be left as-is. Signed-off-by: Eric Sandeen Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

xfs: remove unused flag arguments

2019-06-12T16:00:00+00:00

There are several functions which take a flag argument that is only ever passed as "0," so remove these arguments. Signed-off-by: Eric Sandeen Reviewed-by: Brian Foster Reviewed-by: Bill O'Donnell Reviewed-by: Allison Collins Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong

xfs: separate inode geometry

2019-06-12T15:37:40+00:00

Separate the inode geometry information into a distinct structure. Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner