kernel/git/stable/linux.git/fs/xfs, branch linux-5.8.y

xfs: make sure the rt allocator doesn't run off the end

2020-10-29T09:08:25+00:00

[ Upstream commit 2a6ca4baed620303d414934aa1b7b0a8e7bab05f ] There's an overflow bug in the realtime allocator. If the rt volume is large enough to handle a single allocation request that is larger than the maximum bmap extent length and the rt bitmap ends exactly on a bitmap block boundary, it's possible that the near allocator will try to check the freeness of a range that extends past the end of the bitmap. This fails with a corruption error and shuts down the fs. Therefore, constrain maxlen so that the range scan cannot run off the end of the rt bitmap. Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Signed-off-by: Sasha Levin

xfs: fix high key handling in the rt allocator's query_range function

2020-10-29T09:07:54+00:00

[ Upstream commit d88850bd5516a77c6f727e8b6cefb64e0cc929c7 ] Fix some off-by-one errors in xfs_rtalloc_query_range. The highest key in the realtime bitmap is always one less than the number of rt extents, which means that the key clamp at the start of the function is wrong. The 4th argument to xfs_rtfind_forw is the highest rt extent that we want to probe, which means that passing 1 less than the high key is wrong. Finally, drop the rem variable that controls the loop because we can compare the iteration point (rtstart) against the high key directly. The sordid history of this function is that the original commit (fb3c3) incorrectly passed (high_rec->ar_startblock - 1) as the 'limit' parameter to xfs_rtfind_forw. This was wrong because the "high key" is supposed to be the largest key for which the caller wants result rows, not the key for the first row that could possibly be outside the range that the caller wants to see. A subsequent attempt (8ad56) to strengthen the parameter checking added incorrect clamping of the parameters to the number of rt blocks in the system (despite the bitmap functions all taking units of rt extents) to avoid querying ranges past the end of rt bitmap file but failed to fix the incorrect _rtfind_forw parameter. The original _rtfind_forw parameter error then survived the conversion of the startblock and blockcount fields to rt extents (a0e5c), and the most recent off-by-one fix (a3a37) thought it was patching a problem when the end of the rt volume is not in use, but none of these fixes actually solved the original problem that the author was confused about the "limit" argument to xfs_rtfind_forw. Sadly, all four of these patches were written by this author and even his own usage of this function and rt testing were inadequate to get this fixed quickly. Original-problem: fb3c3de2f65c ("xfs: add a couple of queries to iterate free extents in the rtbitmap") Not-fixed-by: 8ad560d2565e ("xfs: strengthen rtalloc query range checks") Not-fixed-by: a0e5c435babd ("xfs: fix xfs_rtalloc_rec units") Fixes: a3a374bf1889 ("xfs: fix off-by-one error in xfs_rtalloc_query_range") Signed-off-by: Darrick J. Wong Reviewed-by: Chandan Babu R Signed-off-by: Sasha Levin

xfs: fix deadlock and streamline xfs_getfsmap performance

2020-10-29T09:07:54+00:00

[ Upstream commit 8ffa90e1145c70c7ac47f14b59583b2296d89e72 ] Refactor xfs_getfsmap to improve its performance: instead of indirectly calling a function that copies one record to userspace at a time, create a shadow buffer in the kernel and copy the whole array once at the end. On the author's computer, this reduces the runtime on his /home by ~20%. This also eliminates a deadlock when running GETFSMAP against the realtime device. The current code locks the rtbitmap to create fsmappings and copies them into userspace, having not released the rtbitmap lock. If the userspace buffer is an mmap of a sparse file that itself resides on the realtime device, the write page fault will recurse into the fs for allocation, which will deadlock on the rtbitmap lock. Fixes: 4c934c7dd60c ("xfs: report realtime space information via the rtbitmap") Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Chandan Babu R Signed-off-by: Sasha Levin

xfs: limit entries returned when counting fsmap records

2020-10-29T09:07:53+00:00

[ Upstream commit acd1ac3aa22fd58803a12d26b1ab7f70232f8d8d ] If userspace asked fsmap to count the number of entries, we cannot return more than UINT_MAX entries because fmh_entries is u32. Therefore, stop counting if we hit this limit or else we will waste time to return truncated results. Fixes: e89c041338ed ("xfs: implement the GETFSMAP ioctl") Signed-off-by: Darrick J. Wong Reviewed-by: Christoph Hellwig Reviewed-by: Chandan Babu R Signed-off-by: Sasha Levin

xfs: fix finobt btree block recovery ordering

2020-10-29T09:07:53+00:00

[ Upstream commit 671459676ab0e1d371c8d6b184ad1faa05b6941e ] Nathan popped up on #xfs and pointed out that we fail to handle finobt btree blocks in xlog_recover_get_buf_lsn(). This means they always fall through the entire magic number matching code to "recover immediately". Whilst most of the time this is the correct behaviour, occasionally it will be incorrect and could potentially overwrite more recent metadata because we don't check the LSN in the on disk metadata at all. This bug has been present since the finobt was first introduced, and is a potential cause of the occasional xfs_iget_check_free_state() failures we see that indicate that the inode btree state does not match the on disk inode state. Fixes: aafc3c246529 ("xfs: support the XFS_BTNUM_FINOBT free inode btree type") Reported-by: Nathan Scott Signed-off-by: Dave Chinner Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster Signed-off-by: Sasha Levin

xfs: force the log after remapping a synchronous-writes file

2020-10-29T09:07:38+00:00

[ Upstream commit 5ffce3cc22a0e89813ed0c7162a68b639aef9ab6 ] Commit 5833112df7e9 tried to make it so that a remap operation would force the log out to disk if the filesystem is mounted with mandatory synchronous writes. Unfortunately, that commit failed to handle the case where the inode or the file descriptor require mandatory synchronous writes. Refactor the check into into a helper that will look for all three conditions, and now we can treat reflink just like any other synchronous write. Fixes: 5833112df7e9 ("xfs: reflink should force the log out if mounted with wsync") Signed-off-by: Darrick J. Wong Reviewed-by: Brian Foster Reviewed-by: Christoph Hellwig Signed-off-by: Sasha Levin

xfs: initialize the shortform attr header padding entry

2020-09-17T11:55:34+00:00

[ Upstream commit 125eac243806e021f33a1fdea3687eccbb9f7636 ] Don't leak kernel memory contents into the shortform attr fork. Signed-off-by: Darrick J. Wong Reviewed-by: Eric Sandeen Reviewed-by: Dave Chinner Reviewed-by: Christoph Hellwig Signed-off-by: Sasha Levin

xfs: fix off-by-one in inode alloc block reservation calculation

2020-09-17T11:55:33+00:00

[ Upstream commit 657f101930bc6c5b41bd7d6c22565c4302a80d33 ] The inode chunk allocation transaction reserves inobt_maxlevels-1 blocks to accommodate a full split of the inode btree. A full split requires an allocation for every existing level and a new root block, which means inobt_maxlevels is the worst case block requirement for a transaction that inserts to the inobt. This can lead to a transaction block reservation overrun when tmpfile creation allocates an inode chunk and expands the inobt to its maximum depth. This problem has been observed in conjunction with overlayfs, which makes frequent use of tmpfiles internally. The existing reservation code goes back as far as the Linux git repo history (v2.6.12). It was likely never observed as a problem because the traditional file/directory creation transactions also include worst case block reservation for directory modifications, which most likely is able to make up for a single block deficiency in the inode allocation portion of the calculation. tmpfile support is relatively more recent (v3.15), less heavily used, and only includes the inode allocation block reservation as tmpfiles aren't linked into the directory tree on creation. Fix up the inode alloc block reservation macro and a couple of the block allocator minleft parameters that enforce an allocation to leave enough free blocks in the AG for a full inobt split. Signed-off-by: Brian Foster Reviewed-by: Darrick J. Wong Signed-off-by: Darrick J. Wong Signed-off-by: Sasha Levin

xfs: don't update mtime on COW faults

2020-09-09T17:14:25+00:00

commit b17164e258e3888d376a7434415013175d637377 upstream. When running in a dax mode, if the user maps a page with MAP_PRIVATE and PROT_WRITE, the xfs filesystem would incorrectly update ctime and mtime when the user hits a COW fault. This breaks building of the Linux kernel. How to reproduce: 1. extract the Linux kernel tree on dax-mounted xfs filesystem 2. run make clean 3. run make -j12 4. run make -j12 at step 4, make would incorrectly rebuild the whole kernel (although it was already built in step 3). The reason for the breakage is that almost all object files depend on objtool. When we run objtool, it takes COW page fault on its .data section, and these faults will incorrectly update the timestamp of the objtool binary. The updated timestamp causes make to rebuild the whole tree. Signed-off-by: Mikulas Patocka Cc: stable@vger.kernel.org Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

xfs: fix xfs_bmap_validate_extent_raw when checking attr fork of rt files

2020-09-09T17:14:22+00:00

[ Upstream commit d0c20d38af135b2b4b90aa59df7878ef0c8fbef4 ] The realtime flag only applies to the data fork, so don't use the realtime block number checks on the attr fork of a realtime file. Fixes: 30b0984d9117 ("xfs: refactor bmap record validation") Signed-off-by: Darrick J. Wong Reviewed-by: Eric Sandeen Signed-off-by: Sasha Levin