linux.git/fs/xfs, branch v4.20

xfs: fix inverted return from xfs_btree_sblock_verify_crc

2018-12-04T16:50:49+00:00

xfs_btree_sblock_verify_crc is a bool so should not be returning
a failaddr_t; worse, if xfs_log_check_lsn fails it returns
__this_address which looks like a boolean true (i.e. success)
to the caller.

(interestingly xfs_btree_lblock_verify_crc doesn't have the issue)

Signed-off-by: Eric Sandeen 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

xfs: fix PAGE_MASK usage in xfs_free_file_space

2018-12-04T16:50:49+00:00

In commit e53c4b598, I *tried* to teach xfs to force writeback when we
fzero/fpunch right up to EOF so that if EOF is in the middle of a page,
the post-EOF part of the page gets zeroed before we return to userspace.
Unfortunately, I missed the part where PAGE_MASK is ~(PAGE_SIZE - 1),
which means that we totally fail to zero if we're fpunching and EOF is
within the first page.  Worse yet, the same PAGE_MASK thinko plagues the
filemap_write_and_wait_range call, so we'd initiate writeback of the
entire file, which (mostly) masked the thinko.

Drop the tricky PAGE_MASK and replace it with correct usage of PAGE_SIZE
and the proper rounding macros.

Fixes: e53c4b598 ("xfs: ensure post-EOF zeroing happens after zeroing part of a file")
Signed-off-by: Darrick J. Wong 
Reviewed-by: Dave Chinner 
Reviewed-by: Christoph Hellwig

fs/xfs: fix f_ffree value for statfs when project quota is set

2018-11-26T23:01:37+00:00

When project is set, we should use inode limit minus the used count

Signed-off-by: Ye Yin 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

xfs: delalloc -> unwritten COW fork allocation can go wrong

2018-11-21T18:10:53+00:00

Long saga. There have been days spent following this through dead end
after dead end in multi-GB event traces. This morning, after writing
a trace-cmd wrapper that enabled me to be more selective about XFS
trace points, I discovered that I could get just enough essential
tracepoints enabled that there was a 50:50 chance the fsx config
would fail at ~115k ops. If it didn't fail at op 115547, I stopped
fsx at op 115548 anyway.

That gave me two traces - one where the problem manifested, and one
where it didn't. After refining the traces to have the necessary
information, I found that in the failing case there was a real
extent in the COW fork compared to an unwritten extent in the
working case.

Walking back through the two traces to the point where the CWO fork
extents actually diverged, I found that the bad case had an extra
unwritten extent in it. This is likely because the bug it led me to
had triggered multiple times in those 115k ops, leaving stray
COW extents around. What I saw was a COW delalloc conversion to an
unwritten extent (as they should always be through
xfs_iomap_write_allocate()) resulted in a /written extent/:

xfs_writepage: dev 259:0 ino 0x83 pgoff 0x17000 size 0x79a00 offset 0 length 0
xfs_iext_remove: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/2 offset 32 block 152 count 20 flag 1 caller xfs_bmap_add_extent_delay_real
xfs_bmap_pre_update: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/1 offset 1 block 4503599627239429 count 31 flag 0 caller xfs_bmap_add_extent_delay_real
xfs_bmap_post_update: dev 259:0 ino 0x83 state RC|LF|RF|COW cur 0xffff888247b899c0/1 offset 1 block 121 count 51 flag 0 caller xfs_bmap_add_ex

Basically, Cow fork before:

0 1 32 52
+H+DDDDDDDDDDDD+UUUUUUUUUUU+
PREV RIGHT

COW delalloc conversion allocates:

1 32
+uuuuuuuuuuuu+
NEW

And the result according to the xfs_bmap_post_update trace was:

0 1 32 52
+H+wwwwwwwwwwwwwwwwwwwwwwww+
PREV

Which is clearly wrong - it should be a merged unwritten extent,
not an unwritten extent.

That lead me to look at the LEFT_FILLING|RIGHT_FILLING|RIGHT_CONTIG
case in xfs_bmap_add_extent_delay_real(), and sure enough, there's
the bug.

It takes the old delalloc extent (PREV) and adds the length of the
RIGHT extent to it, takes the start block from NEW, removes the
RIGHT extent and then updates PREV with the new extent.

What it fails to do is update PREV.br_state. For delalloc, this is
always XFS_EXT_NORM, while in this case we are converting the
delayed allocation to unwritten, so it needs to be updated to
XFS_EXT_UNWRITTEN. This LF|RF|RC case does not do this, and so
the resultant extent is always written.

And that's the bug I've been chasing for a week - a bmap btree bug,
not a reflink/dedupe/copy_file_range bug, but a BMBT bug introduced
with the recent in core extent tree scalability enhancements.

Signed-off-by: Dave Chinner
Reviewed-by: Christoph Hellwig
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong

xfs: flush removing page cache in xfs_reflink_remap_prep

2018-11-21T18:10:53+00:00

On a sub-page block size filesystem, fsx is failing with a data
corruption after a series of operations involving copying a file
with the destination offset beyond EOF of the destination of the file:

8093(157 mod 256): TRUNCATE DOWN        from 0x7a120 to 0x50000 ******WWWW
8094(158 mod 256): INSERT 0x25000 thru 0x25fff  (0x1000 bytes)
8095(159 mod 256): COPY 0x18000 thru 0x1afff    (0x3000 bytes) to 0x2f400
8096(160 mod 256): WRITE    0x5da00 thru 0x651ff        (0x7800 bytes) HOLE
8097(161 mod 256): COPY 0x2000 thru 0x5fff      (0x4000 bytes) to 0x6fc00

The second copy here is beyond EOF, and it is to sub-page (4k) but
block aligned (1k) offset. The clone runs the EOF zeroing, landing
in a pre-existing post-eof delalloc extent. This zeroes the post-eof
extents in the page cache just fine, dirtying the pages correctly.

The problem is that xfs_reflink_remap_prep() now truncates the page
cache over the range that it is copying it to, and rounds that down
to cover the entire start page. This removes the dirty page over the
delalloc extent from the page cache without having written it back.
Hence later, when the page cache is flushed, the page at offset
0x6f000 has not been written back and hence exposes stale data,
which fsx trips over less than 10 operations later.

Fix this by changing xfs_reflink_remap_prep() to use
xfs_flush_unmap_range().

Signed-off-by: Dave Chinner 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

xfs: extent shifting doesn't fully invalidate page cache

2018-11-20T18:36:19+00:00

The extent shifting code uses a flush and invalidate mechainsm prior
to shifting extents around. This is similar to what
xfs_free_file_space() does, but it doesn't take into account things
like page cache vs block size differences, and it will fail if there
is a page that it currently busy.

xfs_flush_unmap_range() handles all of these cases, so just convert
xfs_prepare_shift() to us that mechanism rather than having it's own
special sauce.

Signed-off-by: Dave Chinner 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

xfs: finobt AG reserves don't consider last AG can be a runt

2018-11-20T18:36:11+00:00

The last AG may be very small comapred to all other AGs, and hence
AG reservations based on the superblock AG size may actually consume
more space than the AG actually has. This results on assert failures
like:

XFS: Assertion failed: xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved + xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <= pag->pagf_freeblks + pag->pagf_flcount, file: fs/xfs/libxfs/xfs_ag_resv.c, line: 319
[   48.932891]  xfs_ag_resv_init+0x1bd/0x1d0
[   48.933853]  xfs_fs_reserve_ag_blocks+0x37/0xb0
[   48.934939]  xfs_mountfs+0x5b3/0x920
[   48.935804]  xfs_fs_fill_super+0x462/0x640
[   48.936784]  ? xfs_test_remount_options+0x60/0x60
[   48.937908]  mount_bdev+0x178/0x1b0
[   48.938751]  mount_fs+0x36/0x170
[   48.939533]  vfs_kern_mount.part.43+0x54/0x130
[   48.940596]  do_mount+0x20e/0xcb0
[   48.941396]  ? memdup_user+0x3e/0x70
[   48.942249]  ksys_mount+0xba/0xd0
[   48.943046]  __x64_sys_mount+0x21/0x30
[   48.943953]  do_syscall_64+0x54/0x170
[   48.944835]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Hence we need to ensure the finobt per-ag space reservations take
into account the size of the last AG rather than treat it like all
the other full size AGs.

Note that both refcountbt and rmapbt already take the size of the AG
into account via reading the AGF length directly.

Signed-off-by: Dave Chinner 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

xfs: fix transient reference count error in xfs_buf_resubmit_failed_buffers

2018-11-20T18:36:01+00:00

When retrying a failed inode or dquot buffer,
xfs_buf_resubmit_failed_buffers() clears all the failed flags from
the inde/dquot log items. In doing so, it also drops all the
reference counts on the buffer that the failed log items hold. This
means it can drop all the active references on the buffer and hence
free the buffer before it queues it for write again.

Putting the buffer on the delwri queue takes a reference to the
buffer (so that it hangs around until it has been written and
completed), but this goes bang if the buffer has already been freed.

Hence we need to add the buffer to the delwri queue before we remove
the failed flags from the log items attached to the buffer to ensure
it always remains referenced during the resubmit process.

Reported-by: Josef Bacik 
Signed-off-by: Dave Chinner 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

xfs: uncached buffer tracing needs to print bno

2018-11-20T18:35:05+00:00

Useless:

xfs_buf_get_uncached: dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_unlock:       dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_submit:       dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_hold:         dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_iowait:       dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_iodone:       dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_iowait_done:  dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_rele:         dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...

Useful:


xfs_buf_get_uncached: dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_unlock:       dev 253:32 bno 0xffffffffffffffff nblks 0x1 ...
xfs_buf_submit:       dev 253:32 bno 0x200b5 nblks 0x1 ...
xfs_buf_hold:         dev 253:32 bno 0x200b5 nblks 0x1 ...
xfs_buf_iowait:       dev 253:32 bno 0x200b5 nblks 0x1 ...
xfs_buf_iodone:       dev 253:32 bno 0x200b5 nblks 0x1 ...
xfs_buf_iowait_done:  dev 253:32 bno 0x200b5 nblks 0x1 ...
xfs_buf_rele:         dev 253:32 bno 0x200b5 nblks 0x1 ...

Signed-off-by: Dave Chinner 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong

xfs: make xfs_file_remap_range() static

2018-11-19T21:30:38+00:00

xfs_file_remap_range() is only used in fs/xfs/xfs_file.c, so make it
static.

This addresses a gcc warning when -Wmissing-prototypes is enabled.

Signed-off-by: Eric Biggers 
Reviewed-by: Darrick J. Wong 
Signed-off-by: Darrick J. Wong