xfs: don't use current->journal_info

commit f2e812c1522dab847912309b00abcc762dd696da upstream.

syzbot reported an ext4 panic during a page fault where found a
journal handle when it didn't expect t

xfs: don't use current->journal_info

commit f2e812c1522dab847912309b00abcc762dd696da upstream.

syzbot reported an ext4 panic during a page fault where found a
journal handle when it didn't expect to find one. The structure
it tripped over had a value of 'TRAN' in the first entry in the
structure, and that indicates it tripped over a struct xfs_trans
instead of a jbd2 handle.

The reason for this is that the page fault was taken during a
copy-out to a user buffer from an xfs bulkstat operation. XFS uses
an "empty" transaction context for bulkstat to do automated metadata
buffer cleanup, and so the transaction context is valid across the
copyout of the bulkstat info into the user buffer.

We are using empty transaction contexts like this in XFS to reduce
the risk of failing to release objects we reference during the
operation, especially during error handling. Hence we really need to
ensure that we can take page faults from these contexts without
leaving landmines for the code processing the page fault to trip
over.

However, this same behaviour could happen from any other filesystem
that triggers a page fault or any other exception that is handled
on-stack from within a task context that has current->journal_info
set. Having a page fault from some other filesystem bounce into XFS
where we have to run a transaction isn't a bug at all, but the usage
of current->journal_info means that this could result corruption of
the outer task's journal_info structure.

The problem is purely that we now have two different contexts that
now think they own current->journal_info. IOWs, no filesystem can
allow page faults or on-stack exceptions while current->journal_info
is set by the filesystem because the exception processing might use
current->journal_info itself.

If we end up with nested XFS transactions whilst holding an empty
transaction, then it isn't an issue as the outer transaction does
not hold a log reservation. If we ignore the current->journal_info
usage, then the only problem that might occur is a deadlock if the
exception tries to take the same locks the upper context holds.
That, however, is not a problem that setting current->journal_info
would solve, so it's largely an irrelevant concern here.

IOWs, we really only use current->journal_info for a warning check
in xfs_vm_writepages() to ensure we aren't doing writeback from a
transaction context. Writeback might need to do allocation, so it
can need to run transactions itself. Hence it's a debug check to
warn us that we've done something silly, and largely it is not all
that useful.

So let's just remove all the use of current->journal_info in XFS and
get rid of all the potential issues from nested contexts where
current->journal_info might get misused by another filesystem
context.

Reported-by: syzbot+cdee56dbcdf0096ef605@syzkaller.appspotmail.com
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Mark Tinguely <mark.tinguely@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

xfs: don't use current->journal_info

commit f2e812c1522dab847912309b00abcc762dd696da upstream.

syzbot reported an ext4 panic during a page fault where found a
journal handle when it didn't expect t

xfs: don't use current->journal_info

commit f2e812c1522dab847912309b00abcc762dd696da upstream.

syzbot reported an ext4 panic during a page fault where found a
journal handle when it didn't expect to find one. The structure
it tripped over had a value of 'TRAN' in the first entry in the
structure, and that indicates it tripped over a struct xfs_trans
instead of a jbd2 handle.

The reason for this is that the page fault was taken during a
copy-out to a user buffer from an xfs bulkstat operation. XFS uses
an "empty" transaction context for bulkstat to do automated metadata
buffer cleanup, and so the transaction context is valid across the
copyout of the bulkstat info into the user buffer.

We are using empty transaction contexts like this in XFS to reduce
the risk of failing to release objects we reference during the
operation, especially during error handling. Hence we really need to
ensure that we can take page faults from these contexts without
leaving landmines for the code processing the page fault to trip
over.

However, this same behaviour could happen from any other filesystem
that triggers a page fault or any other exception that is handled
on-stack from within a task context that has current->journal_info
set. Having a page fault from some other filesystem bounce into XFS
where we have to run a transaction isn't a bug at all, but the usage
of current->journal_info means that this could result corruption of
the outer task's journal_info structure.

The problem is purely that we now have two different contexts that
now think they own current->journal_info. IOWs, no filesystem can
allow page faults or on-stack exceptions while current->journal_info
is set by the filesystem because the exception processing might use
current->journal_info itself.

If we end up with nested XFS transactions whilst holding an empty
transaction, then it isn't an issue as the outer transaction does
not hold a log reservation. If we ignore the current->journal_info
usage, then the only problem that might occur is a deadlock if the
exception tries to take the same locks the upper context holds.
That, however, is not a problem that setting current->journal_info
would solve, so it's largely an irrelevant concern here.

IOWs, we really only use current->journal_info for a warning check
in xfs_vm_writepages() to ensure we aren't doing writeback from a
transaction context. Writeback might need to do allocation, so it
can need to run transactions itself. Hence it's a debug check to
warn us that we've done something silly, and largely it is not all
that useful.

So let's just remove all the use of current->journal_info in XFS and
get rid of all the potential issues from nested contexts where
current->journal_info might get misused by another filesystem
context.

Reported-by: syzbot+cdee56dbcdf0096ef605@syzkaller.appspotmail.com
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Reviewed-by: Mark Tinguely <mark.tinguely@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
Signed-off-by: Catherine Hoang <catherine.hoang@oracle.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

fs/xfs: Fix typos in comments

Delete duplicate word "the"

[chandan: Fix mangled patch]
Signed-off-by: Zizhen Pang <pangzizhen001@208suo.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-

fs/xfs: Fix typos in comments

Delete duplicate word "the"

[chandan: Fix mangled patch]
Signed-off-by: Zizhen Pang <pangzizhen001@208suo.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>

show more ...

iomap: Add per-block dirty state tracking to improve performance

When filesystem blocksize is less than folio size (either with
mapping_large_folio_support() or with blocksize < pagesize) and when t

iomap: Add per-block dirty state tracking to improve performance

When filesystem blocksize is less than folio size (either with
mapping_large_folio_support() or with blocksize < pagesize) and when the
folio is uptodate in pagecache, then even a byte write can cause
an entire folio to be written to disk during writeback. This happens
because we currently don't have a mechanism to track per-block dirty
state within struct iomap_folio_state. We currently only track uptodate
state.

This patch implements support for tracking per-block dirty state in
iomap_folio_state->state bitmap. This should help improve the filesystem
write performance and help reduce write amplification.

Performance testing of below fio workload reveals ~16x performance
improvement using nvme with XFS (4k blocksize) on Power (64K pagesize)
FIO reported write bw scores improved from around ~28 MBps to ~452 MBps.

1. <test_randwrite.fio>
[global]
ioengine=psync
rw=randwrite
overwrite=1
pre_read=1
direct=0
bs=4k
size=1G
dir=./
numjobs=8
fdatasync=1
runtime=60
iodepth=64
group_reporting=1

[fio-run]

2. Also our internal performance team reported that this patch improves
their database workload performance by around ~83% (with XFS on Power)

Reported-by: Aravinda Herle <araherle@in.ibm.com>
Reported-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: set FMODE_CAN_ODIRECT instead of a dummy direct_IO method

Since commit a2ad63daa88b ("VFS: add FMODE_CAN_ODIRECT file flag") file
systems can just set the FMODE_CAN_ODIRECT flag at open time in

xfs: set FMODE_CAN_ODIRECT instead of a dummy direct_IO method

Since commit a2ad63daa88b ("VFS: add FMODE_CAN_ODIRECT file flag") file
systems can just set the FMODE_CAN_ODIRECT flag at open time instead of
wiring up a dummy direct_IO method to indicate support for direct I/O.
Do that for xfs so that noop_direct_IO can eventually be removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: fix off-by-one-block in xfs_discard_folio()

The recent writeback corruption fixes changed the code in
xfs_discard_folio() to calculate a byte range to for punching
delalloc extents. A mistake w

xfs: fix off-by-one-block in xfs_discard_folio()

The recent writeback corruption fixes changed the code in
xfs_discard_folio() to calculate a byte range to for punching
delalloc extents. A mistake was made in using round_up(pos) for the
end offset, because when pos points at the first byte of a block, it
does not get rounded up to point to the end byte of the block. hence
the punch range is short, and this leads to unexpected behaviour in
certain cases in xfs_bmap_punch_delalloc_range.

e.g. pos = 0 means we call xfs_bmap_punch_delalloc_range(0,0), so
there is no previous extent and it rounds up the punch to the end of
the delalloc extent it found at offset 0, not the end of the range
given to xfs_bmap_punch_delalloc_range().

Fix this by handling the zero block offset case correctly.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=217030
Link: https://lore.kernel.org/linux-xfs/Y+vOfaxIWX1c%2Fyy9@bfoster/
Fixes: 7348b322332d ("xfs: xfs_bmap_punch_delalloc_range() should take a byte range")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Found-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: add debug knob to slow down writeback for fun

Add a new error injection knob so that we can arbitrarily slow down
writeback to test for race conditions and aberrant reclaim behavior if
the writ

xfs: add debug knob to slow down writeback for fun

Add a new error injection knob so that we can arbitrarily slow down
writeback to test for race conditions and aberrant reclaim behavior if
the writeback mechanisms are slow to issue writeback. This will enable
functional testing for the ifork sequence counters introduced in commit
745b3f76d1c8 ("xfs: maintain a sequence count for inode fork
manipulations").

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>

show more ...

xfs: use iomap_valid method to detect stale cached iomaps

Now that iomap supports a mechanism to validate cached iomaps for
buffered write operations, hook it up to the XFS buffered write ops
so tha

xfs: use iomap_valid method to detect stale cached iomaps

Now that iomap supports a mechanism to validate cached iomaps for
buffered write operations, hook it up to the XFS buffered write ops
so that we can avoid data corruptions that result from stale cached
iomaps. See:

https://lore.kernel.org/linux-xfs/20220817093627.GZ3600936@dread.disaster.area/

or the ->iomap_valid() introduction commit for exact details of the
corruption vector.

The validity cookie we store in the iomap is based on the type of
iomap we return. It is expected that the iomap->flags we set in
xfs_bmbt_to_iomap() is not perturbed by the iomap core and are
returned to us in the iomap passed via the .iomap_valid() callback.
This ensures that the validity cookie is always checking the correct
inode fork sequence numbers to detect potential changes that affect
the extent cached by the iomap.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: xfs_bmap_punch_delalloc_range() should take a byte range

All the callers of xfs_bmap_punch_delalloc_range() jump through
hoops to convert a byte range to filesystem blocks before calling
xfs_bm

xfs: xfs_bmap_punch_delalloc_range() should take a byte range

All the callers of xfs_bmap_punch_delalloc_range() jump through
hoops to convert a byte range to filesystem blocks before calling
xfs_bmap_punch_delalloc_range(). Instead, pass the byte range to
xfs_bmap_punch_delalloc_range() and have it do the conversion to
filesystem blocks internally.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

mm/migrate: Add filemap_migrate_folio()

There is nothing iomap-specific about iomap_migratepage(), and it fits
a pattern used by several other filesystems, so move it to mm/migrate.c,
convert it to

mm/migrate: Add filemap_migrate_folio()

There is nothing iomap-specific about iomap_migratepage(), and it fits
a pattern used by several other filesystems, so move it to mm/migrate.c,
convert it to be filemap_migrate_folio() and convert the iomap filesystems
to use it.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

iomap: don't invalidate folios after writeback errors

XFS has the unique behavior (as compared to the other Linux filesystems)
that on writeback errors it will completely invalidate the affected
fol

iomap: don't invalidate folios after writeback errors

XFS has the unique behavior (as compared to the other Linux filesystems)
that on writeback errors it will completely invalidate the affected
folio and force the page cache to reread the contents from disk. All
other filesystems leave the page mapped and up to date.

This is a rude awakening for user programs, since (in the case where
write fails but reread doesn't) file contents will appear to revert to
old disk contents with no notification other than an EIO on fsync. This
might have been annoying back in the days when iomap dealt with one page
at a time, but with multipage folios, we can now throw away *megabytes*
worth of data for a single write error.

On *most* Linux filesystems, a program can respond to an EIO on write by
redirtying the entire file and scheduling it for writeback. This isn't
foolproof, since the page that failed writeback is no longer dirty and
could be evicted, but programs that want to recover properly *also*
have to detect XFS and regenerate every write they've made to the file.

When running xfs/314 on arm64, I noticed a UAF when xfs_discard_folio
invalidates multipage folios that could be undergoing writeback. If,
say, we have a 256K folio caching a mix of written and unwritten
extents, it's possible that we could start writeback of the first (say)
64K of the folio and then hit a writeback error on the next 64K. We
then free the iop attached to the folio, which is really bad because
writeback completion on the first 64k will trip over the "blocks per
folio > 1 && !iop" assertion.

This can't be fixed by only invalidating the folio if writeback fails at
the start of the folio, since the folio is marked !uptodate, which trips
other assertions elsewhere. Get rid of the whole behavior entirely.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

show more ...

iomap: Convert to release_folio

Change all the filesystems which used iomap_releasepage to use the
new function.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jeff Layto

iomap: Convert to release_folio

Change all the filesystems which used iomap_releasepage to use the
new function.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jeff Layton <jlayton@kernel.org>

show more ...

fs: Convert iomap_readpage to iomap_read_folio

A straightforward conversion as iomap_readpage already worked in folios.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>

fs: Convert __set_page_dirty_no_writeback to noop_dirty_folio

This is a mechanical change.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@open

fs: Convert __set_page_dirty_no_writeback to noop_dirty_folio

This is a mechanical change.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

show more ...

fs: Convert trivial uses of __set_page_dirty_nobuffers to filemap_dirty_folio

These filesystems use __set_page_dirty_nobuffers() either directly or
with a very thin wrapper; convert them en masse.

fs: Convert trivial uses of __set_page_dirty_nobuffers to filemap_dirty_folio

These filesystems use __set_page_dirty_nobuffers() either directly or
with a very thin wrapper; convert them en masse.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

show more ...

fs: Remove noop_invalidatepage()

We used to have to use noop_invalidatepage() to prevent
block_invalidatepage() from being called, but that behaviour is now gone.

Signed-off-by: Matthew Wilcox (Ora

fs: Remove noop_invalidatepage()

We used to have to use noop_invalidatepage() to prevent
block_invalidatepage() from being called, but that behaviour is now gone.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

show more ...

iomap: Remove iomap_invalidatepage()

Use iomap_invalidate_folio() in all the iomap-based filesystems
and rename the iomap_invalidatepage tracepoint.

Signed-off-by: Matthew Wilcox (Oracle) <willy@in

iomap: Remove iomap_invalidatepage()

Use iomap_invalidate_folio() in all the iomap-based filesystems
and rename the iomap_invalidatepage tracepoint.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Tested-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Acked-by: Damien Le Moal <damien.lemoal@opensource.wdc.com>
Tested-by: Mike Marshall <hubcap@omnibond.com> # orangefs
Tested-by: David Howells <dhowells@redhat.com> # afs

show more ...

xfs, iomap: limit individual ioend chain lengths in writeback

Trond Myklebust reported soft lockups in XFS IO completion such as
this:

watchdog: BUG: soft lockup - CPU#12 stuck for 23s! [kworker/1

xfs, iomap: limit individual ioend chain lengths in writeback

Trond Myklebust reported soft lockups in XFS IO completion such as
this:

watchdog: BUG: soft lockup - CPU#12 stuck for 23s! [kworker/12:1:3106]
CPU: 12 PID: 3106 Comm: kworker/12:1 Not tainted 4.18.0-305.10.2.el8_4.x86_64 #1
Workqueue: xfs-conv/md127 xfs_end_io [xfs]
RIP: 0010:_raw_spin_unlock_irqrestore+0x11/0x20
Call Trace:
wake_up_page_bit+0x8a/0x110
iomap_finish_ioend+0xd7/0x1c0
iomap_finish_ioends+0x7f/0xb0
xfs_end_ioend+0x6b/0x100 [xfs]
xfs_end_io+0xb9/0xe0 [xfs]
process_one_work+0x1a7/0x360
worker_thread+0x1fa/0x390
kthread+0x116/0x130
ret_from_fork+0x35/0x40

Ioends are processed as an atomic completion unit when all the
chained bios in the ioend have completed their IO. Logically
contiguous ioends can also be merged and completed as a single,
larger unit. Both of these things can be problematic as both the
bio chains per ioend and the size of the merged ioends processed as
a single completion are both unbound.

If we have a large sequential dirty region in the page cache,
write_cache_pages() will keep feeding us sequential pages and we
will keep mapping them into ioends and bios until we get a dirty
page at a non-sequential file offset. These large sequential runs
can will result in bio and ioend chaining to optimise the io
patterns. The pages iunder writeback are pinned within these chains
until the submission chaining is broken, allowing the entire chain
to be completed. This can result in huge chains being processed
in IO completion context.

We get deep bio chaining if we have large contiguous physical
extents. We will keep adding pages to the current bio until it is
full, then we'll chain a new bio to keep adding pages for writeback.
Hence we can build bio chains that map millions of pages and tens of
gigabytes of RAM if the page cache contains big enough contiguous
dirty file regions. This long bio chain pins those pages until the
final bio in the chain completes and the ioend can iterate all the
chained bios and complete them.

OTOH, if we have a physically fragmented file, we end up submitting
one ioend per physical fragment that each have a small bio or bio
chain attached to them. We do not chain these at IO submission time,
but instead we chain them at completion time based on file
offset via iomap_ioend_try_merge(). Hence we can end up with unbound
ioend chains being built via completion merging.

XFS can then do COW remapping or unwritten extent conversion on that
merged chain, which involves walking an extent fragment at a time
and running a transaction to modify the physical extent information.
IOWs, we merge all the discontiguous ioends together into a
contiguous file range, only to then process them individually as
discontiguous extents.

This extent manipulation is computationally expensive and can run in
a tight loop, so merging logically contiguous but physically
discontigous ioends gains us nothing except for hiding the fact the
fact we broke the ioends up into individual physical extents at
submission and then need to loop over those individual physical
extents at completion.

Hence we need to have mechanisms to limit ioend sizes and
to break up completion processing of large merged ioend chains:

1. bio chains per ioend need to be bound in length. Pure overwrites
go straight to iomap_finish_ioend() in softirq context with the
exact bio chain attached to the ioend by submission. Hence the only
way to prevent long holdoffs here is to bound ioend submission
sizes because we can't reschedule in softirq context.

2. iomap_finish_ioends() has to handle unbound merged ioend chains
correctly. This relies on any one call to iomap_finish_ioend() being
bound in runtime so that cond_resched() can be issued regularly as
the long ioend chain is processed. i.e. this relies on mechanism #1
to limit individual ioend sizes to work correctly.

3. filesystems have to loop over the merged ioends to process
physical extent manipulations. This means they can loop internally,
and so we break merging at physical extent boundaries so the
filesystem can easily insert reschedule points between individual
extent manipulations.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reported-and-tested-by: Trond Myklebust <trondmy@hammerspace.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

show more ...

iomap,xfs: Convert ->discard_page to ->discard_folio

XFS has the only implementation of ->discard_page today, so convert it
to use folios in the same patch as converting the API.

Signed-off-by: Mat

iomap,xfs: Convert ->discard_page to ->discard_folio

XFS has the only implementation of ->discard_page today, so convert it
to use folios in the same patch as converting the API.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: pass the mapping flags to xfs_bmbt_to_iomap

To prepare for looking at the IOMAP_DAX flag in xfs_bmbt_to_iomap pass in
the input mapping flags to xfs_bmbt_to_iomap.

Signed-off-by: Christoph Hel

xfs: pass the mapping flags to xfs_bmbt_to_iomap

To prepare for looking at the IOMAP_DAX flag in xfs_bmbt_to_iomap pass in
the input mapping flags to xfs_bmbt_to_iomap.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Link: https://lore.kernel.org/r/20211129102203.2243509-24-hch@lst.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

show more ...

xfs: punch out data fork delalloc blocks on COW writeback failure

If writeback I/O to a COW extent fails, the COW fork blocks are
punched out and the data fork blocks left alone. It is possible for

xfs: punch out data fork delalloc blocks on COW writeback failure

If writeback I/O to a COW extent fails, the COW fork blocks are
punched out and the data fork blocks left alone. It is possible for
COW fork blocks to overlap non-shared data fork blocks (due to
cowextsz hint prealloc), however, and writeback unconditionally maps
to the COW fork whenever blocks exist at the corresponding offset of
the page undergoing writeback. This means it's quite possible for a
COW fork extent to overlap delalloc data fork blocks, writeback to
convert and map to the COW fork blocks, writeback to fail, and
finally for ioend completion to cancel the COW fork blocks and leave
stale data fork delalloc blocks around in the inode. The blocks are
effectively stale because writeback failure also discards dirty page
state.

If this occurs, it is likely to trigger assert failures, free space
accounting corruption and failures in unrelated file operations. For
example, a subsequent reflink attempt of the affected file to a new
target file will trip over the stale delalloc in the source file and
fail. Several of these issues are occasionally reproduced by
generic/648, but are reproducible on demand with the right sequence
of operations and timely I/O error injection.

To fix this problem, update the ioend failure path to also punch out
underlying data fork delalloc blocks on I/O error. This is analogous
to the writeback submission failure path in xfs_discard_page() where
we might fail to map data fork delalloc blocks and consistent with
the successful COW writeback completion path, which is responsible
for unmapping from the data fork and remapping in COW fork blocks.

Fixes: 787eb485509f ("xfs: fix and streamline error handling in xfs_end_io")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>

show more ...

xfs: punch out data fork delalloc blocks on COW writeback failure

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punche

xfs: punch out data fork delalloc blocks on COW writeback failure

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punched out and the data fork blocks left alone. It is possible for
COW fork blocks to overlap non-shared data fork blocks (due to
cowextsz hint prealloc), however, and writeback unconditionally maps
to the COW fork whenever blocks exist at the corresponding offset of
the page undergoing writeback. This means it's quite possible for a
COW fork extent to overlap delalloc data fork blocks, writeback to
convert and map to the COW fork blocks, writeback to fail, and
finally for ioend completion to cancel the COW fork blocks and leave
stale data fork delalloc blocks around in the inode. The blocks are
effectively stale because writeback failure also discards dirty page
state.

If this occurs, it is likely to trigger assert failures, free space
accounting corruption and failures in unrelated file operations. For
example, a subsequent reflink attempt of the affected file to a new
target file will trip over the stale delalloc in the source file and
fail. Several of these issues are occasionally reproduced by
generic/648, but are reproducible on demand with the right sequence
of operations and timely I/O error injection.

To fix this problem, update the ioend failure path to also punch out
underlying data fork delalloc blocks on I/O error. This is analogous
to the writeback submission failure path in xfs_discard_page() where
we might fail to map data fork delalloc blocks and consistent with
the successful COW writeback completion path, which is responsible
for unmapping from the data fork and remapping in COW fork blocks.

Fixes: 787eb485509f ("xfs: fix and streamline error handling in xfs_end_io")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

xfs: punch out data fork delalloc blocks on COW writeback failure

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punche

xfs: punch out data fork delalloc blocks on COW writeback failure

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punched out and the data fork blocks left alone. It is possible for
COW fork blocks to overlap non-shared data fork blocks (due to
cowextsz hint prealloc), however, and writeback unconditionally maps
to the COW fork whenever blocks exist at the corresponding offset of
the page undergoing writeback. This means it's quite possible for a
COW fork extent to overlap delalloc data fork blocks, writeback to
convert and map to the COW fork blocks, writeback to fail, and
finally for ioend completion to cancel the COW fork blocks and leave
stale data fork delalloc blocks around in the inode. The blocks are
effectively stale because writeback failure also discards dirty page
state.

If this occurs, it is likely to trigger assert failures, free space
accounting corruption and failures in unrelated file operations. For
example, a subsequent reflink attempt of the affected file to a new
target file will trip over the stale delalloc in the source file and
fail. Several of these issues are occasionally reproduced by
generic/648, but are reproducible on demand with the right sequence
of operations and timely I/O error injection.

To fix this problem, update the ioend failure path to also punch out
underlying data fork delalloc blocks on I/O error. This is analogous
to the writeback submission failure path in xfs_discard_page() where
we might fail to map data fork delalloc blocks and consistent with
the successful COW writeback completion path, which is responsible
for unmapping from the data fork and remapping in COW fork blocks.

Fixes: 787eb485509f ("xfs: fix and streamline error handling in xfs_end_io")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

xfs: punch out data fork delalloc blocks on COW writeback failure

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punche

xfs: punch out data fork delalloc blocks on COW writeback failure

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punched out and the data fork blocks left alone. It is possible for
COW fork blocks to overlap non-shared data fork blocks (due to
cowextsz hint prealloc), however, and writeback unconditionally maps
to the COW fork whenever blocks exist at the corresponding offset of
the page undergoing writeback. This means it's quite possible for a
COW fork extent to overlap delalloc data fork blocks, writeback to
convert and map to the COW fork blocks, writeback to fail, and
finally for ioend completion to cancel the COW fork blocks and leave
stale data fork delalloc blocks around in the inode. The blocks are
effectively stale because writeback failure also discards dirty page
state.

If this occurs, it is likely to trigger assert failures, free space
accounting corruption and failures in unrelated file operations. For
example, a subsequent reflink attempt of the affected file to a new
target file will trip over the stale delalloc in the source file and
fail. Several of these issues are occasionally reproduced by
generic/648, but are reproducible on demand with the right sequence
of operations and timely I/O error injection.

To fix this problem, update the ioend failure path to also punch out
underlying data fork delalloc blocks on I/O error. This is analogous
to the writeback submission failure path in xfs_discard_page() where
we might fail to map data fork delalloc blocks and consistent with
the successful COW writeback completion path, which is responsible
for unmapping from the data fork and remapping in COW fork blocks.

Fixes: 787eb485509f ("xfs: fix and streamline error handling in xfs_end_io")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...

xfs: punch out data fork delalloc blocks on COW writeback failure

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punche

xfs: punch out data fork delalloc blocks on COW writeback failure

[ Upstream commit 5ca5916b6bc93577c360c06cb7cdf71adb9b5faf ]

If writeback I/O to a COW extent fails, the COW fork blocks are
punched out and the data fork blocks left alone. It is possible for
COW fork blocks to overlap non-shared data fork blocks (due to
cowextsz hint prealloc), however, and writeback unconditionally maps
to the COW fork whenever blocks exist at the corresponding offset of
the page undergoing writeback. This means it's quite possible for a
COW fork extent to overlap delalloc data fork blocks, writeback to
convert and map to the COW fork blocks, writeback to fail, and
finally for ioend completion to cancel the COW fork blocks and leave
stale data fork delalloc blocks around in the inode. The blocks are
effectively stale because writeback failure also discards dirty page
state.

If this occurs, it is likely to trigger assert failures, free space
accounting corruption and failures in unrelated file operations. For
example, a subsequent reflink attempt of the affected file to a new
target file will trip over the stale delalloc in the source file and
fail. Several of these issues are occasionally reproduced by
generic/648, but are reproducible on demand with the right sequence
of operations and timely I/O error injection.

To fix this problem, update the ioend failure path to also punch out
underlying data fork delalloc blocks on I/O error. This is analogous
to the writeback submission failure path in xfs_discard_page() where
we might fail to map data fork delalloc blocks and consistent with
the successful COW writeback completion path, which is responsible
for unmapping from the data fork and remapping in COW fork blocks.

Fixes: 787eb485509f ("xfs: fix and streamline error handling in xfs_end_io")
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Leah Rumancik <leah.rumancik@gmail.com>
Acked-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

show more ...