4.11-stable updates for XFS

4.11-stable updates for XFS

[Christoph Hellwig]

Hi all,

below are backports up to (almost) 4.12-rc4 for XFS.  I've selected all
clear bugfixes for reported bugs.  One patch is a little odd as it's a
subset of a patch that went into mainline, which included a bit of
infrastructure in addition to the new feature, and we only need the
infrastructure for stable.  Also a fs/iomap.c fix for code only used
by XFS is included.

[sorry for the resend, one commit contained an existing stable@ Cc
 with a "#" sign in it that made the mail server throw up.  This also
 means you might get these commits twice, but the whole set here is
 one that passed xfstests testing]

[PATCH 01/23] xfs: use dedicated log worker wq to avoid deadlock with cil wq

[Christoph Hellwig]

From: Brian Foster <bfoster@redhat.com>

commit 696a562072e3c14bcd13ae5acc19cdf27679e865 upstream.

The log covering background task used to be part of the xfssyncd
workqueue. That workqueue was removed as of commit 5889608df ("xfs:
syncd workqueue is no more") and the associated work item scheduled
to the xfs-log wq. The latter is used for log buffer I/O completion.

Since xfs_log_worker() can invoke a log flush, a deadlock is
possible between the xfs-log and xfs-cil workqueues. Consider the
following codepath from xfs_log_worker():

xfs_log_worker()
  xfs_log_force()
    _xfs_log_force()
      xlog_cil_force()
        xlog_cil_force_lsn()
          xlog_cil_push_now()
            flush_work()

The above is in xfs-log wq context and blocked waiting on the
completion of an xfs-cil work item. Concurrently, the cil push in
progress can end up blocked here:

xlog_cil_push_work()
  xlog_cil_push()
    xlog_write()
      xlog_state_get_iclog_space()
        xlog_wait(&log->l_flush_wait, ...)

The above is in xfs-cil context waiting on log buffer I/O
completion, which executes in xfs-log wq context. In this scenario
both workqueues are deadlocked waiting on eachother.

Add a new workqueue specifically for the high level log covering and
ail pushing worker, as was the case prior to commit 5889608df.

Diagnosed-by: David Jeffery <djeffery@redhat.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_log.c   | 2 +-
 fs/xfs/xfs_mount.h | 1 +
 fs/xfs/xfs_super.c | 8 ++++++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index b1469f0a91a6..bb58cd1873c9 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1293,7 +1293,7 @@ void
 xfs_log_work_queue(
 	struct xfs_mount        *mp)
 {
-	queue_delayed_work(mp->m_log_workqueue, &mp->m_log->l_work,
+	queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work,
 				msecs_to_jiffies(xfs_syncd_centisecs * 10));
 }
 
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index 6db6fd6b82b0..22b2185e93a0 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -183,6 +183,7 @@ typedef struct xfs_mount {
 	struct workqueue_struct	*m_reclaim_workqueue;
 	struct workqueue_struct	*m_log_workqueue;
 	struct workqueue_struct *m_eofblocks_workqueue;
+	struct workqueue_struct	*m_sync_workqueue;
 
 	/*
 	 * Generation of the filesysyem layout.  This is incremented by each
diff --git a/fs/xfs/xfs_super.c b/fs/xfs/xfs_super.c
index 685c042a120f..47d239dcf3f4 100644
--- a/fs/xfs/xfs_super.c
+++ b/fs/xfs/xfs_super.c
@@ -877,8 +877,15 @@ xfs_init_mount_workqueues(
 	if (!mp->m_eofblocks_workqueue)
 		goto out_destroy_log;
 
+	mp->m_sync_workqueue = alloc_workqueue("xfs-sync/%s", WQ_FREEZABLE, 0,
+					       mp->m_fsname);
+	if (!mp->m_sync_workqueue)
+		goto out_destroy_eofb;
+
 	return 0;
 
+out_destroy_eofb:
+	destroy_workqueue(mp->m_eofblocks_workqueue);
 out_destroy_log:
 	destroy_workqueue(mp->m_log_workqueue);
 out_destroy_reclaim:
@@ -899,6 +906,7 @@ STATIC void
 xfs_destroy_mount_workqueues(
 	struct xfs_mount	*mp)
 {
+	destroy_workqueue(mp->m_sync_workqueue);
 	destroy_workqueue(mp->m_eofblocks_workqueue);
 	destroy_workqueue(mp->m_log_workqueue);
 	destroy_workqueue(mp->m_reclaim_workqueue);
-- 
2.11.0

[PATCH 02/23] xfs: fix over-copying of getbmap parameters from userspace

[Christoph Hellwig]

From: "Darrick J. Wong" <darrick.wong@oracle.com>

commit be6324c00c4d1e0e665f03ed1fc18863a88da119 upstream.

In xfs_ioc_getbmap, we should only copy the fields of struct getbmap
from userspace, or else we end up copying random stack contents into the
kernel.  struct getbmap is a strict subset of getbmapx, so a partial
structure copy should work fine.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_ioctl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 2fd7fdf5438f..6d30b06e79bc 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1543,10 +1543,11 @@ xfs_ioc_getbmap(
 	unsigned int		cmd,
 	void			__user *arg)
 {
-	struct getbmapx		bmx;
+	struct getbmapx		bmx = { 0 };
 	int			error;
 
-	if (copy_from_user(&bmx, arg, sizeof(struct getbmapx)))
+	/* struct getbmap is a strict subset of struct getbmapx. */
+	if (copy_from_user(&bmx, arg, offsetof(struct getbmapx, bmv_iflags)))
 		return -EFAULT;
 
 	if (bmx.bmv_count < 2)
-- 
2.11.0

[PATCH 03/23] xfs: actually report xattr extents via iomap

[Christoph Hellwig]

From: "Darrick J. Wong" <darrick.wong@oracle.com>

commit 84358536dc355a9c8978ee425f87e116186bed16 upstream.

Apparently FIEMAP for xattrs has been broken since we switched to
the iomap backend because of an incorrect check for xattr presence.
Also fix the broken locking.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_iomap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 288ee5b840d7..79e6dfac3dd6 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1170,10 +1170,10 @@ xfs_xattr_iomap_begin(
 	if (XFS_FORCED_SHUTDOWN(mp))
 		return -EIO;
 
-	lockmode = xfs_ilock_data_map_shared(ip);
+	lockmode = xfs_ilock_attr_map_shared(ip);
 
 	/* if there are no attribute fork or extents, return ENOENT */
-	if (XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) {
+	if (!XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) {
 		error = -ENOENT;
 		goto out_unlock;
 	}
-- 
2.11.0

[PATCH 04/23] xfs: drop iolock from reclaim context to appease lockdep

[Christoph Hellwig]

From: Brian Foster <bfoster@redhat.com>

commit 3b4683c294095b5f777c03307ef8c60f47320e12 upstream.

Lockdep complains about use of the iolock in inode reclaim context
because it doesn't understand that reclaim has the last reference to
the inode, and thus an iolock->reclaim->iolock deadlock is not
possible.

The iolock is technically not necessary in xfs_inactive() and was
only added to appease an assert in xfs_free_eofblocks(), which can
be called from other non-reclaim contexts. Therefore, just kill the
assert and drop the use of the iolock from reclaim context to quiet
lockdep.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_bmap_util.c | 8 +++-----
 fs/xfs/xfs_inode.c     | 9 +++++----
 2 files changed, 8 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 828532ce0adc..cad4e3e2df00 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -904,9 +904,9 @@ xfs_can_free_eofblocks(struct xfs_inode *ip, bool force)
 }
 
 /*
- * This is called by xfs_inactive to free any blocks beyond eof
- * when the link count isn't zero and by xfs_dm_punch_hole() when
- * punching a hole to EOF.
+ * This is called to free any blocks beyond eof. The caller must hold
+ * IOLOCK_EXCL unless we are in the inode reclaim path and have the only
+ * reference to the inode.
  */
 int
 xfs_free_eofblocks(
@@ -921,8 +921,6 @@ xfs_free_eofblocks(
 	struct xfs_bmbt_irec	imap;
 	struct xfs_mount	*mp = ip->i_mount;
 
-	ASSERT(xfs_isilocked(ip, XFS_IOLOCK_EXCL));
-
 	/*
 	 * Figure out if there are any blocks beyond the end
 	 * of the file.  If not, then there is nothing to do.
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 7605d8396596..ec9826c56500 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1906,12 +1906,13 @@ xfs_inactive(
 		 * force is true because we are evicting an inode from the
 		 * cache. Post-eof blocks must be freed, lest we end up with
 		 * broken free space accounting.
+		 *
+		 * Note: don't bother with iolock here since lockdep complains
+		 * about acquiring it in reclaim context. We have the only
+		 * reference to the inode at this point anyways.
 		 */
-		if (xfs_can_free_eofblocks(ip, true)) {
-			xfs_ilock(ip, XFS_IOLOCK_EXCL);
+		if (xfs_can_free_eofblocks(ip, true))
 			xfs_free_eofblocks(ip);
-			xfs_iunlock(ip, XFS_IOLOCK_EXCL);
-		}
 
 		return;
 	}
-- 
2.11.0

[PATCH 05/23] xfs: fix integer truncation in xfs_bmap_remap_alloc

[Christoph Hellwig]

commit 52813fb13ff90bd9c39a93446cbf1103c290b6e9 upstream.

bno should be a xfs_fsblock_t, which is 64-bit wides instead of a
xfs_aglock_t, which truncates the value to 32 bits.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_bmap.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 9bd104f32908..2a426d127e05 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3863,7 +3863,7 @@ xfs_bmap_remap_alloc(
 {
 	struct xfs_trans	*tp = ap->tp;
 	struct xfs_mount	*mp = tp->t_mountp;
-	xfs_agblock_t		bno;
+	xfs_fsblock_t		bno;
 	struct xfs_alloc_arg	args;
 	int			error;
 
-- 
2.11.0

[PATCH 06/23] xfs: handle array index overrun in xfs_dir2_leaf_readbuf()

[Christoph Hellwig]

From: Eric Sandeen <sandeen@redhat.com>

commit 023cc840b40fad95c6fe26fff1d380a8c9d45939 upstream.

Carlos had a case where "find" seemed to start spinning
forever and never return.

This was on a filesystem with non-default multi-fsb (8k)
directory blocks, and a fragmented directory with extents
like this:

0:[0,133646,2,0]
1:[2,195888,1,0]
2:[3,195890,1,0]
3:[4,195892,1,0]
4:[5,195894,1,0]
5:[6,195896,1,0]
6:[7,195898,1,0]
7:[8,195900,1,0]
8:[9,195902,1,0]
9:[10,195908,1,0]
10:[11,195910,1,0]
11:[12,195912,1,0]
12:[13,195914,1,0]
...

i.e. the first extent is a contiguous 2-fsb dir block, but
after that it is fragmented into 1 block extents.

At the top of the readdir path, we allocate a mapping array
which (for this filesystem geometry) can hold 10 extents; see
the assignment to map_info->map_size.  During readdir, we are
therefore able to map extents 0 through 9 above into the array
for readahead purposes.  If we count by 2, we see that the last
mapped index (9) is the first block of a 2-fsb directory block.

At the end of xfs_dir2_leaf_readbuf() we have 2 loops to fill
more readahead; the outer loop assumes one full dir block is
processed each loop iteration, and an inner loop that ensures
that this is so by advancing to the next extent until a full
directory block is mapped.

The problem is that this inner loop may step past the last
extent in the mapping array as it tries to reach the end of
the directory block.  This will read garbage for the extent
length, and as a result the loop control variable 'j' may
become corrupted and never fail the loop conditional.

The number of valid mappings we have in our array is stored
in map->map_valid, so stop this inner loop based on that limit.

There is an ASSERT at the top of the outer loop for this
same condition, but we never made it out of the inner loop,
so the ASSERT never fired.

Huge appreciation for Carlos for debugging and isolating
the problem.

Debugged-and-analyzed-by: Carlos Maiolino <cmaiolino@redhat.com>
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Tested-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Bill O'Donnell <billodo@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_dir2_readdir.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
index ad9396e516f6..c45de729c74e 100644
--- a/fs/xfs/xfs_dir2_readdir.c
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -394,6 +394,7 @@ xfs_dir2_leaf_readbuf(
 
 	/*
 	 * Do we need more readahead?
+	 * Each loop tries to process 1 full dir blk; last may be partial.
 	 */
 	blk_start_plug(&plug);
 	for (mip->ra_index = mip->ra_offset = i = 0;
@@ -425,9 +426,14 @@ xfs_dir2_leaf_readbuf(
 		}
 
 		/*
-		 * Advance offset through the mapping table.
+		 * Advance offset through the mapping table, processing a full
+		 * dir block even if it is fragmented into several extents.
+		 * But stop if we have consumed all valid mappings, even if
+		 * it's not yet a full directory block.
 		 */
-		for (j = 0; j < geo->fsbcount; j += length ) {
+		for (j = 0;
+		     j < geo->fsbcount && mip->ra_index < mip->map_valid;
+		     j += length ) {
 			/*
 			 * The rest of this extent but not more than a dir
 			 * block.
-- 
2.11.0

[PATCH 07/23] xfs: prevent multi-fsb dir readahead from reading random blocks

[Christoph Hellwig]

From: Brian Foster <bfoster@redhat.com>

commit cb52ee334a45ae6c78a3999e4b473c43ddc528f4 upstream.

Directory block readahead uses a complex iteration mechanism to map
between high-level directory blocks and underlying physical extents.
This mechanism attempts to traverse the higher-level dir blocks in a
manner that handles multi-fsb directory blocks and simultaneously
maintains a reference to the corresponding physical blocks.

This logic doesn't handle certain (discontiguous) physical extent
layouts correctly with multi-fsb directory blocks. For example,
consider the case of a 4k FSB filesystem with a 2 FSB (8k) directory
block size and a directory with the following extent layout:

 EXT: FILE-OFFSET      BLOCK-RANGE      AG AG-OFFSET        TOTAL
   0: [0..7]:          88..95            0 (88..95)             8
   1: [8..15]:         80..87            0 (80..87)             8
   2: [16..39]:        168..191          0 (168..191)          24
   3: [40..63]:        5242952..5242975  1 (72..95)            24

Directory block 0 spans physical extents 0 and 1, dirblk 1 lies
entirely within extent 2 and dirblk 2 spans extents 2 and 3. Because
extent 2 is larger than the directory block size, the readahead code
erroneously assumes the block is contiguous and issues a readahead
based on the physical mapping of the first fsb of the dirblk. This
results in read verifier failure and a spurious corruption or crc
failure, depending on the filesystem format.

Further, the subsequent readahead code responsible for walking
through the physical table doesn't correctly advance the physical
block reference for dirblk 2. Instead of advancing two physical
filesystem blocks, the first iteration of the loop advances 1 block
(correctly), but the subsequent iteration advances 2 more physical
blocks because the next physical extent (extent 3, above) happens to
cover more than dirblk 2. At this point, the higher-level directory
block walking is completely off the rails of the actual physical
layout of the directory for the respective mapping table.

Update the contiguous dirblock logic to consider the current offset
in the physical extent to avoid issuing directory readahead to
unrelated blocks. Also, update the mapping table advancing code to
consider the current offset within the current dirblock to avoid
advancing the mapping reference too far beyond the dirblock.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_dir2_readdir.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_dir2_readdir.c b/fs/xfs/xfs_dir2_readdir.c
index c45de729c74e..20b7a5c6eb2f 100644
--- a/fs/xfs/xfs_dir2_readdir.c
+++ b/fs/xfs/xfs_dir2_readdir.c
@@ -405,7 +405,8 @@ xfs_dir2_leaf_readbuf(
 		 * Read-ahead a contiguous directory block.
 		 */
 		if (i > mip->ra_current &&
-		    map[mip->ra_index].br_blockcount >= geo->fsbcount) {
+		    (map[mip->ra_index].br_blockcount - mip->ra_offset) >=
+		    geo->fsbcount) {
 			xfs_dir3_data_readahead(dp,
 				map[mip->ra_index].br_startoff + mip->ra_offset,
 				XFS_FSB_TO_DADDR(dp->i_mount,
@@ -438,7 +439,7 @@ xfs_dir2_leaf_readbuf(
 			 * The rest of this extent but not more than a dir
 			 * block.
 			 */
-			length = min_t(int, geo->fsbcount,
+			length = min_t(int, geo->fsbcount - j,
 					map[mip->ra_index].br_blockcount -
 							mip->ra_offset);
 			mip->ra_offset += length;
-- 
2.11.0

[PATCH 08/23] xfs: fix up quotacheck buffer list error handling

[Christoph Hellwig]

From: Brian Foster <bfoster@redhat.com>

commit 20e8a063786050083fe05b4f45be338c60b49126 upstream.

The quotacheck error handling of the delwri buffer list assumes the
resident buffers are locked and doesn't clear the _XBF_DELWRI_Q flag
on the buffers that are dequeued. This can lead to assert failures
on buffer release and possibly other locking problems.

Move this code to a delwri queue cancel helper function to
encapsulate the logic required to properly release buffers from a
delwri queue. Update the helper to clear the delwri queue flag and
call it from quotacheck.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_buf.c | 24 ++++++++++++++++++++++++
 fs/xfs/xfs_buf.h |  1 +
 fs/xfs/xfs_qm.c  |  7 +------
 3 files changed, 26 insertions(+), 6 deletions(-)

diff --git a/fs/xfs/xfs_buf.c b/fs/xfs/xfs_buf.c
index b6208728ba39..ba036c11be94 100644
--- a/fs/xfs/xfs_buf.c
+++ b/fs/xfs/xfs_buf.c
@@ -1079,6 +1079,8 @@ void
 xfs_buf_unlock(
 	struct xfs_buf		*bp)
 {
+	ASSERT(xfs_buf_islocked(bp));
+
 	XB_CLEAR_OWNER(bp);
 	up(&bp->b_sema);
 
@@ -1815,6 +1817,28 @@ xfs_alloc_buftarg(
 }
 
 /*
+ * Cancel a delayed write list.
+ *
+ * Remove each buffer from the list, clear the delwri queue flag and drop the
+ * associated buffer reference.
+ */
+void
+xfs_buf_delwri_cancel(
+	struct list_head	*list)
+{
+	struct xfs_buf		*bp;
+
+	while (!list_empty(list)) {
+		bp = list_first_entry(list, struct xfs_buf, b_list);
+
+		xfs_buf_lock(bp);
+		bp->b_flags &= ~_XBF_DELWRI_Q;
+		list_del_init(&bp->b_list);
+		xfs_buf_relse(bp);
+	}
+}
+
+/*
  * Add a buffer to the delayed write list.
  *
  * This queues a buffer for writeout if it hasn't already been.  Note that
diff --git a/fs/xfs/xfs_buf.h b/fs/xfs/xfs_buf.h
index 3c867e5a63e1..42c1d42e5f89 100644
--- a/fs/xfs/xfs_buf.h
+++ b/fs/xfs/xfs_buf.h
@@ -330,6 +330,7 @@ extern void *xfs_buf_offset(struct xfs_buf *, size_t);
 extern void xfs_buf_stale(struct xfs_buf *bp);
 
 /* Delayed Write Buffer Routines */
+extern void xfs_buf_delwri_cancel(struct list_head *);
 extern bool xfs_buf_delwri_queue(struct xfs_buf *, struct list_head *);
 extern int xfs_buf_delwri_submit(struct list_head *);
 extern int xfs_buf_delwri_submit_nowait(struct list_head *);
diff --git a/fs/xfs/xfs_qm.c b/fs/xfs/xfs_qm.c
index b669b123287b..8b9a9f15f022 100644
--- a/fs/xfs/xfs_qm.c
+++ b/fs/xfs/xfs_qm.c
@@ -1384,12 +1384,7 @@ xfs_qm_quotacheck(
 	mp->m_qflags |= flags;
 
  error_return:
-	while (!list_empty(&buffer_list)) {
-		struct xfs_buf *bp =
-			list_first_entry(&buffer_list, struct xfs_buf, b_list);
-		list_del_init(&bp->b_list);
-		xfs_buf_relse(bp);
-	}
+	xfs_buf_delwri_cancel(&buffer_list);
 
 	if (error) {
 		xfs_warn(mp,
-- 
2.11.0

[PATCH 09/23] xfs: support ability to wait on new inodes

[Christoph Hellwig]

From: Brian Foster <bfoster@redhat.com>

commit 756baca27fff3ecaeab9dbc7a5ee35a1d7bc0c7f upstream.

Inodes that are inserted into the perag tree but still under
construction are flagged with the XFS_INEW bit. Most contexts either
skip such inodes when they are encountered or have the ability to
handle them.

The runtime quotaoff sequence introduces a context that must wait
for construction of such inodes to correctly ensure that all dquots
in the fs are released. In anticipation of this, support the ability
to wait on new inodes. Wake the appropriate bit when XFS_INEW is
cleared.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_icache.c | 5 ++++-
 fs/xfs/xfs_inode.h  | 4 +++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 3531f8f72fa5..25f4f4595821 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -366,14 +366,17 @@ xfs_iget_cache_hit(
 
 		error = xfs_reinit_inode(mp, inode);
 		if (error) {
+			bool wake;
 			/*
 			 * Re-initializing the inode failed, and we are in deep
 			 * trouble.  Try to re-add it to the reclaim list.
 			 */
 			rcu_read_lock();
 			spin_lock(&ip->i_flags_lock);
-
+			wake = !!__xfs_iflags_test(ip, XFS_INEW);
 			ip->i_flags &= ~(XFS_INEW | XFS_IRECLAIM);
+			if (wake)
+				wake_up_bit(&ip->i_flags, __XFS_INEW_BIT);
 			ASSERT(ip->i_flags & XFS_IRECLAIMABLE);
 			trace_xfs_iget_reclaim_fail(ip);
 			goto out_error;
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 10dcf27b4c85..10e89fcb49d7 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -216,7 +216,8 @@ static inline bool xfs_is_reflink_inode(struct xfs_inode *ip)
 #define XFS_IRECLAIM		(1 << 0) /* started reclaiming this inode */
 #define XFS_ISTALE		(1 << 1) /* inode has been staled */
 #define XFS_IRECLAIMABLE	(1 << 2) /* inode can be reclaimed */
-#define XFS_INEW		(1 << 3) /* inode has just been allocated */
+#define __XFS_INEW_BIT		3	 /* inode has just been allocated */
+#define XFS_INEW		(1 << __XFS_INEW_BIT)
 #define XFS_ITRUNCATED		(1 << 5) /* truncated down so flush-on-close */
 #define XFS_IDIRTY_RELEASE	(1 << 6) /* dirty release already seen */
 #define __XFS_IFLOCK_BIT	7	 /* inode is being flushed right now */
@@ -464,6 +465,7 @@ static inline void xfs_finish_inode_setup(struct xfs_inode *ip)
 	xfs_iflags_clear(ip, XFS_INEW);
 	barrier();
 	unlock_new_inode(VFS_I(ip));
+	wake_up_bit(&ip->i_flags, __XFS_INEW_BIT);
 }
 
 static inline void xfs_setup_existing_inode(struct xfs_inode *ip)
-- 
2.11.0

[PATCH 10/23] xfs: update ag iterator to support wait on new inodes

[Christoph Hellwig]

From: Brian Foster <bfoster@redhat.com>

commit ae2c4ac2dd39b23a87ddb14ceddc3f2872c6aef5 upstream.

The AG inode iterator currently skips new inodes as such inodes are
inserted into the inode radix tree before they are fully
constructed. Certain contexts require the ability to wait on the
construction of new inodes, however. The fs-wide dquot release from
the quotaoff sequence is an example of this.

Update the AG inode iterator to support the ability to wait on
inodes flagged with XFS_INEW upon request. Create a new
xfs_inode_ag_iterator_flags() interface and support a set of
iteration flags to modify the iteration behavior. When the
XFS_AGITER_INEW_WAIT flag is set, include XFS_INEW flags in the
radix tree inode lookup and wait on them before the callback is
executed.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_icache.c | 53 +++++++++++++++++++++++++++++++++++++++++++++--------
 fs/xfs/xfs_icache.h |  8 ++++++++
 2 files changed, 53 insertions(+), 8 deletions(-)

diff --git a/fs/xfs/xfs_icache.c b/fs/xfs/xfs_icache.c
index 25f4f4595821..f61c84f8e31a 100644
--- a/fs/xfs/xfs_icache.c
+++ b/fs/xfs/xfs_icache.c
@@ -262,6 +262,22 @@ xfs_inode_clear_reclaim_tag(
 	xfs_perag_clear_reclaim_tag(pag);
 }
 
+static void
+xfs_inew_wait(
+	struct xfs_inode	*ip)
+{
+	wait_queue_head_t *wq = bit_waitqueue(&ip->i_flags, __XFS_INEW_BIT);
+	DEFINE_WAIT_BIT(wait, &ip->i_flags, __XFS_INEW_BIT);
+
+	do {
+		prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
+		if (!xfs_iflags_test(ip, XFS_INEW))
+			break;
+		schedule();
+	} while (true);
+	finish_wait(wq, &wait.wait);
+}
+
 /*
  * When we recycle a reclaimable inode, we need to re-initialise the VFS inode
  * part of the structure. This is made more complex by the fact we store
@@ -626,9 +642,11 @@ xfs_iget(
 
 STATIC int
 xfs_inode_ag_walk_grab(
-	struct xfs_inode	*ip)
+	struct xfs_inode	*ip,
+	int			flags)
 {
 	struct inode		*inode = VFS_I(ip);
+	bool			newinos = !!(flags & XFS_AGITER_INEW_WAIT);
 
 	ASSERT(rcu_read_lock_held());
 
@@ -646,7 +664,8 @@ xfs_inode_ag_walk_grab(
 		goto out_unlock_noent;
 
 	/* avoid new or reclaimable inodes. Leave for reclaim code to flush */
-	if (__xfs_iflags_test(ip, XFS_INEW | XFS_IRECLAIMABLE | XFS_IRECLAIM))
+	if ((!newinos && __xfs_iflags_test(ip, XFS_INEW)) ||
+	    __xfs_iflags_test(ip, XFS_IRECLAIMABLE | XFS_IRECLAIM))
 		goto out_unlock_noent;
 	spin_unlock(&ip->i_flags_lock);
 
@@ -674,7 +693,8 @@ xfs_inode_ag_walk(
 					   void *args),
 	int			flags,
 	void			*args,
-	int			tag)
+	int			tag,
+	int			iter_flags)
 {
 	uint32_t		first_index;
 	int			last_error = 0;
@@ -716,7 +736,7 @@ xfs_inode_ag_walk(
 		for (i = 0; i < nr_found; i++) {
 			struct xfs_inode *ip = batch[i];
 
-			if (done || xfs_inode_ag_walk_grab(ip))
+			if (done || xfs_inode_ag_walk_grab(ip, iter_flags))
 				batch[i] = NULL;
 
 			/*
@@ -744,6 +764,9 @@ xfs_inode_ag_walk(
 		for (i = 0; i < nr_found; i++) {
 			if (!batch[i])
 				continue;
+			if ((iter_flags & XFS_AGITER_INEW_WAIT) &&
+			    xfs_iflags_test(batch[i], XFS_INEW))
+				xfs_inew_wait(batch[i]);
 			error = execute(batch[i], flags, args);
 			IRELE(batch[i]);
 			if (error == -EAGAIN) {
@@ -823,12 +846,13 @@ xfs_cowblocks_worker(
 }
 
 int
-xfs_inode_ag_iterator(
+xfs_inode_ag_iterator_flags(
 	struct xfs_mount	*mp,
 	int			(*execute)(struct xfs_inode *ip, int flags,
 					   void *args),
 	int			flags,
-	void			*args)
+	void			*args,
+	int			iter_flags)
 {
 	struct xfs_perag	*pag;
 	int			error = 0;
@@ -838,7 +862,8 @@ xfs_inode_ag_iterator(
 	ag = 0;
 	while ((pag = xfs_perag_get(mp, ag))) {
 		ag = pag->pag_agno + 1;
-		error = xfs_inode_ag_walk(mp, pag, execute, flags, args, -1);
+		error = xfs_inode_ag_walk(mp, pag, execute, flags, args, -1,
+					  iter_flags);
 		xfs_perag_put(pag);
 		if (error) {
 			last_error = error;
@@ -850,6 +875,17 @@ xfs_inode_ag_iterator(
 }
 
 int
+xfs_inode_ag_iterator(
+	struct xfs_mount	*mp,
+	int			(*execute)(struct xfs_inode *ip, int flags,
+					   void *args),
+	int			flags,
+	void			*args)
+{
+	return xfs_inode_ag_iterator_flags(mp, execute, flags, args, 0);
+}
+
+int
 xfs_inode_ag_iterator_tag(
 	struct xfs_mount	*mp,
 	int			(*execute)(struct xfs_inode *ip, int flags,
@@ -866,7 +902,8 @@ xfs_inode_ag_iterator_tag(
 	ag = 0;
 	while ((pag = xfs_perag_get_tag(mp, ag, tag))) {
 		ag = pag->pag_agno + 1;
-		error = xfs_inode_ag_walk(mp, pag, execute, flags, args, tag);
+		error = xfs_inode_ag_walk(mp, pag, execute, flags, args, tag,
+					  0);
 		xfs_perag_put(pag);
 		if (error) {
 			last_error = error;
diff --git a/fs/xfs/xfs_icache.h b/fs/xfs/xfs_icache.h
index 8a7c849b4dea..9183f77958ef 100644
--- a/fs/xfs/xfs_icache.h
+++ b/fs/xfs/xfs_icache.h
@@ -48,6 +48,11 @@ struct xfs_eofblocks {
 #define XFS_IGET_UNTRUSTED	0x2
 #define XFS_IGET_DONTCACHE	0x4
 
+/*
+ * flags for AG inode iterator
+ */
+#define XFS_AGITER_INEW_WAIT	0x1	/* wait on new inodes */
+
 int xfs_iget(struct xfs_mount *mp, struct xfs_trans *tp, xfs_ino_t ino,
 	     uint flags, uint lock_flags, xfs_inode_t **ipp);
 
@@ -79,6 +84,9 @@ void xfs_cowblocks_worker(struct work_struct *);
 int xfs_inode_ag_iterator(struct xfs_mount *mp,
 	int (*execute)(struct xfs_inode *ip, int flags, void *args),
 	int flags, void *args);
+int xfs_inode_ag_iterator_flags(struct xfs_mount *mp,
+	int (*execute)(struct xfs_inode *ip, int flags, void *args),
+	int flags, void *args, int iter_flags);
 int xfs_inode_ag_iterator_tag(struct xfs_mount *mp,
 	int (*execute)(struct xfs_inode *ip, int flags, void *args),
 	int flags, void *args, int tag);
-- 
2.11.0

[PATCH 11/23] xfs: wait on new inodes during quotaoff dquot release

[Christoph Hellwig]

From: Brian Foster <bfoster@redhat.com>

commit e20c8a517f259cb4d258e10b0cd5d4b30d4167a0 upstream.

The quotaoff operation has a race with inode allocation that results
in a livelock. An inode allocation that occurs before the quota
status flags are updated acquires the appropriate dquots for the
inode via xfs_qm_vop_dqalloc(). It then inserts the XFS_INEW inode
into the perag radix tree, sometime later attaches the dquots to the
inode and finally clears the XFS_INEW flag. Quotaoff expects to
release the dquots from all inodes in the filesystem via
xfs_qm_dqrele_all_inodes(). This invokes the AG inode iterator,
which skips inodes in the XFS_INEW state because they are not fully
constructed. If the scan occurs after dquots have been attached to
an inode, but before XFS_INEW is cleared, the newly allocated inode
will continue to hold a reference to the applicable dquots. When
quotaoff invokes xfs_qm_dqpurge_all(), the reference count of those
dquot(s) remain elevated and the dqpurge scan spins indefinitely.

To address this problem, update the xfs_qm_dqrele_all_inodes() scan
to wait on inodes marked on the XFS_INEW state. We wait on the
inodes explicitly rather than skip and retry to avoid continuous
retry loops due to a parallel inode allocation workload. Since
quotaoff updates the quota state flags and uses a synchronous
transaction before the dqrele scan, and dquots are attached to
inodes after radix tree insertion iff quota is enabled, one INEW
waiting pass through the AG guarantees that the scan has processed
all inodes that could possibly hold dquot references.

Reported-by: Eryu Guan <eguan@redhat.com>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_qm_syscalls.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_qm_syscalls.c b/fs/xfs/xfs_qm_syscalls.c
index 475a3882a81f..9cb5c381b01c 100644
--- a/fs/xfs/xfs_qm_syscalls.c
+++ b/fs/xfs/xfs_qm_syscalls.c
@@ -759,5 +759,6 @@ xfs_qm_dqrele_all_inodes(
 	uint		 flags)
 {
 	ASSERT(mp->m_quotainfo);
-	xfs_inode_ag_iterator(mp, xfs_dqrele_inode, flags, NULL);
+	xfs_inode_ag_iterator_flags(mp, xfs_dqrele_inode, flags, NULL,
+				    XFS_AGITER_INEW_WAIT);
 }
-- 
2.11.0

[PATCH 12/23] xfs: reserve enough blocks to handle btree splits when remapping

[Christoph Hellwig]

From: "Darrick J. Wong" <darrick.wong@oracle.com>

commit fe0be23e68200573de027de9b8cc2b27e7fce35e upstream.

In xfs_reflink_end_cow, we erroneously reserve only enough blocks to
handle adding 1 extent.  This is problematic if we fragment free space,
have to do CoW, and then have to perform multiple bmap btree expansions.
Furthermore, the BUI recovery routine doesn't reserve /any/ blocks to
handle btree splits, so log recovery fails after our first error causes
the filesystem to go down.

Therefore, refactor the transaction block reservation macros until we
have a macro that works for our deferred (re)mapping activities, and fix
both problems by using that macro.

With 1k blocks we can hit this fairly often in g/187 if the scratch fs
is big enough.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/libxfs/xfs_trans_space.h | 23 +++++++++++++++++------
 fs/xfs/xfs_bmap_item.c          |  5 ++++-
 fs/xfs/xfs_reflink.c            | 18 ++++++++++++++++--
 3 files changed, 37 insertions(+), 9 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_trans_space.h b/fs/xfs/libxfs/xfs_trans_space.h
index 7917f6e44286..d787c677d2a3 100644
--- a/fs/xfs/libxfs/xfs_trans_space.h
+++ b/fs/xfs/libxfs/xfs_trans_space.h
@@ -21,8 +21,20 @@
 /*
  * Components of space reservations.
  */
+
+/* Worst case number of rmaps that can be held in a block. */
 #define XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp)    \
 		(((mp)->m_rmap_mxr[0]) - ((mp)->m_rmap_mnr[0]))
+
+/* Adding one rmap could split every level up to the top of the tree. */
+#define XFS_RMAPADD_SPACE_RES(mp) ((mp)->m_rmap_maxlevels)
+
+/* Blocks we might need to add "b" rmaps to a tree. */
+#define XFS_NRMAPADD_SPACE_RES(mp, b)\
+	(((b + XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp) - 1) / \
+	  XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp)) * \
+	  XFS_RMAPADD_SPACE_RES(mp))
+
 #define XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp)    \
 		(((mp)->m_alloc_mxr[0]) - ((mp)->m_alloc_mnr[0]))
 #define	XFS_EXTENTADD_SPACE_RES(mp,w)	(XFS_BM_MAXLEVELS(mp,w) - 1)
@@ -30,13 +42,12 @@
 	(((b + XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp) - 1) / \
 	  XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp)) * \
 	  XFS_EXTENTADD_SPACE_RES(mp,w))
+
+/* Blocks we might need to add "b" mappings & rmappings to a file. */
 #define XFS_SWAP_RMAP_SPACE_RES(mp,b,w)\
-	(((b + XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp) - 1) / \
-	  XFS_MAX_CONTIG_EXTENTS_PER_BLOCK(mp)) * \
-	  XFS_EXTENTADD_SPACE_RES(mp,w) + \
-	 ((b + XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp) - 1) / \
-	  XFS_MAX_CONTIG_RMAPS_PER_BLOCK(mp)) * \
-	  (mp)->m_rmap_maxlevels)
+	(XFS_NEXTENTADD_SPACE_RES((mp), (b), (w)) + \
+	 XFS_NRMAPADD_SPACE_RES((mp), (b)))
+
 #define	XFS_DAENTER_1B(mp,w)	\
 	((w) == XFS_DATA_FORK ? (mp)->m_dir_geo->fsbcount : 1)
 #define	XFS_DAENTER_DBS(mp,w)	\
diff --git a/fs/xfs/xfs_bmap_item.c b/fs/xfs/xfs_bmap_item.c
index 9bf57c76623b..c4b90e794e41 100644
--- a/fs/xfs/xfs_bmap_item.c
+++ b/fs/xfs/xfs_bmap_item.c
@@ -34,6 +34,8 @@
 #include "xfs_bmap.h"
 #include "xfs_icache.h"
 #include "xfs_trace.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_trans_space.h"
 
 
 kmem_zone_t	*xfs_bui_zone;
@@ -446,7 +448,8 @@ xfs_bui_recover(
 		return -EIO;
 	}
 
-	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate, 0, 0, 0, &tp);
+	error = xfs_trans_alloc(mp, &M_RES(mp)->tr_itruncate,
+			XFS_EXTENTADD_SPACE_RES(mp, XFS_DATA_FORK), 0, 0, &tp);
 	if (error)
 		return error;
 	budp = xfs_trans_get_bud(tp, buip);
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 4a84c5ea266d..20c46d2ff4f5 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -709,8 +709,22 @@ xfs_reflink_end_cow(
 	offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
 	end_fsb = XFS_B_TO_FSB(ip->i_mount, offset + count);
 
-	/* Start a rolling transaction to switch the mappings */
-	resblks = XFS_EXTENTADD_SPACE_RES(ip->i_mount, XFS_DATA_FORK);
+	/*
+	 * Start a rolling transaction to switch the mappings.  We're
+	 * unlikely ever to have to remap 16T worth of single-block
+	 * extents, so just cap the worst case extent count to 2^32-1.
+	 * Stick a warning in just in case, and avoid 64-bit division.
+	 */
+	BUILD_BUG_ON(MAX_RW_COUNT > UINT_MAX);
+	if (end_fsb - offset_fsb > UINT_MAX) {
+		error = -EFSCORRUPTED;
+		xfs_force_shutdown(ip->i_mount, SHUTDOWN_CORRUPT_INCORE);
+		ASSERT(0);
+		goto out;
+	}
+	resblks = XFS_NEXTENTADD_SPACE_RES(ip->i_mount,
+			(unsigned int)(end_fsb - offset_fsb),
+			XFS_DATA_FORK);
 	error = xfs_trans_alloc(ip->i_mount, &M_RES(ip->i_mount)->tr_write,
 			resblks, 0, 0, &tp);
 	if (error)
-- 
2.11.0

[PATCH 13/23] xfs: fix use-after-free in xfs_finish_page_writeback

[Christoph Hellwig]

From: Eryu Guan <eguan@redhat.com>

commit 161f55efba5ddccc690139fae9373cafc3447a97 upstream.

Commit 28b783e47ad7 ("xfs: bufferhead chains are invalid after
end_page_writeback") fixed one use-after-free issue by
pre-calculating the loop conditionals before calling bh->b_end_io()
in the end_io processing loop, but it assigned 'next' pointer before
checking end offset boundary & breaking the loop, at which point the
bh might be freed already, and caused use-after-free.

This is caught by KASAN when running fstests generic/127 on sub-page
block size XFS.

[ 2517.244502] run fstests generic/127 at 2017-04-27 07:30:50
[ 2747.868840] ==================================================================
[ 2747.876949] BUG: KASAN: use-after-free in xfs_destroy_ioend+0x3d3/0x4e0 [xfs] at addr ffff8801395ae698
...
[ 2747.918245] Call Trace:
[ 2747.920975]  dump_stack+0x63/0x84
[ 2747.924673]  kasan_object_err+0x21/0x70
[ 2747.928950]  kasan_report+0x271/0x530
[ 2747.933064]  ? xfs_destroy_ioend+0x3d3/0x4e0 [xfs]
[ 2747.938409]  ? end_page_writeback+0xce/0x110
[ 2747.943171]  __asan_report_load8_noabort+0x19/0x20
[ 2747.948545]  xfs_destroy_ioend+0x3d3/0x4e0 [xfs]
[ 2747.953724]  xfs_end_io+0x1af/0x2b0 [xfs]
[ 2747.958197]  process_one_work+0x5ff/0x1000
[ 2747.962766]  worker_thread+0xe4/0x10e0
[ 2747.966946]  kthread+0x2d3/0x3d0
[ 2747.970546]  ? process_one_work+0x1000/0x1000
[ 2747.975405]  ? kthread_create_on_node+0xc0/0xc0
[ 2747.980457]  ? syscall_return_slowpath+0xe6/0x140
[ 2747.985706]  ? do_page_fault+0x30/0x80
[ 2747.989887]  ret_from_fork+0x2c/0x40
[ 2747.993874] Object at ffff8801395ae690, in cache buffer_head size: 104
[ 2748.001155] Allocated:
[ 2748.003782] PID = 8327
[ 2748.006411]  save_stack_trace+0x1b/0x20
[ 2748.010688]  save_stack+0x46/0xd0
[ 2748.014383]  kasan_kmalloc+0xad/0xe0
[ 2748.018370]  kasan_slab_alloc+0x12/0x20
[ 2748.022648]  kmem_cache_alloc+0xb8/0x1b0
[ 2748.027024]  alloc_buffer_head+0x22/0xc0
[ 2748.031399]  alloc_page_buffers+0xd1/0x250
[ 2748.035968]  create_empty_buffers+0x30/0x410
[ 2748.040730]  create_page_buffers+0x120/0x1b0
[ 2748.045493]  __block_write_begin_int+0x17a/0x1800
[ 2748.050740]  iomap_write_begin+0x100/0x2f0
[ 2748.055308]  iomap_zero_range_actor+0x253/0x5c0
[ 2748.060362]  iomap_apply+0x157/0x270
[ 2748.064347]  iomap_zero_range+0x5a/0x80
[ 2748.068624]  iomap_truncate_page+0x6b/0xa0
[ 2748.073227]  xfs_setattr_size+0x1f7/0xa10 [xfs]
[ 2748.078312]  xfs_vn_setattr_size+0x68/0x140 [xfs]
[ 2748.083589]  xfs_file_fallocate+0x4ac/0x820 [xfs]
[ 2748.088838]  vfs_fallocate+0x2cf/0x780
[ 2748.093021]  SyS_fallocate+0x48/0x80
[ 2748.097006]  do_syscall_64+0x18a/0x430
[ 2748.101186]  return_from_SYSCALL_64+0x0/0x6a
[ 2748.105948] Freed:
[ 2748.108189] PID = 8327
[ 2748.110816]  save_stack_trace+0x1b/0x20
[ 2748.115093]  save_stack+0x46/0xd0
[ 2748.118788]  kasan_slab_free+0x73/0xc0
[ 2748.122969]  kmem_cache_free+0x7a/0x200
[ 2748.127247]  free_buffer_head+0x41/0x80
[ 2748.131524]  try_to_free_buffers+0x178/0x250
[ 2748.136316]  xfs_vm_releasepage+0x2e9/0x3d0 [xfs]
[ 2748.141563]  try_to_release_page+0x100/0x180
[ 2748.146325]  invalidate_inode_pages2_range+0x7da/0xcf0
[ 2748.152087]  xfs_shift_file_space+0x37d/0x6e0 [xfs]
[ 2748.157557]  xfs_collapse_file_space+0x49/0x120 [xfs]
[ 2748.163223]  xfs_file_fallocate+0x2a7/0x820 [xfs]
[ 2748.168462]  vfs_fallocate+0x2cf/0x780
[ 2748.172642]  SyS_fallocate+0x48/0x80
[ 2748.176629]  do_syscall_64+0x18a/0x430
[ 2748.180810]  return_from_SYSCALL_64+0x0/0x6a

Fixed it by checking on offset against end & breaking out first,
dereference bh only if there're still bufferheads to process.

Signed-off-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_aops.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 61494295d92f..a7645be51d87 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -111,11 +111,11 @@ xfs_finish_page_writeback(
 
 	bsize = bh->b_size;
 	do {
+		if (off > end)
+			break;
 		next = bh->b_this_page;
 		if (off < bvec->bv_offset)
 			goto next_bh;
-		if (off > end)
-			break;
 		bh->b_end_io(bh, !error);
 next_bh:
 		off += bsize;
-- 
2.11.0

[PATCH 14/23] xfs: fix indlen accounting error on partial delalloc conversion

[Christoph Hellwig]

From: Brian Foster <bfoster@redhat.com>

commit 0daaecacb83bc6b656a56393ab77a31c28139bc7 upstream.

The delalloc -> real block conversion path uses an incorrect
calculation in the case where the middle part of a delalloc extent
is being converted. This is documented as a rare situation because
XFS generally attempts to maximize contiguity by converting as much
of a delalloc extent as possible.

If this situation does occur, the indlen reservation for the two new
delalloc extents left behind by the conversion of the middle range
is calculated and compared with the original reservation. If more
blocks are required, the delta is allocated from the global block
pool. This delta value can be characterized as the difference
between the new total requirement (temp + temp2) and the currently
available reservation minus those blocks that have already been
allocated (startblockval(PREV.br_startblock) - allocated).

The problem is that the current code does not account for previously
allocated blocks correctly. It subtracts the current allocation
count from the (new - old) delta rather than the old indlen
reservation. This means that more indlen blocks than have been
allocated end up stashed in the remaining extents and free space
accounting is broken as a result.

Fix up the calculation to subtract the allocated block count from
the original extent indlen and thus correctly allocate the
reservation delta based on the difference between the new total
requirement and the unused blocks from the original reservation.
Also remove a bogus assert that contradicts the fact that the new
indlen reservation can be larger than the original indlen
reservation.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_bmap.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 2a426d127e05..6c68f3b888b0 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -2106,8 +2106,10 @@ xfs_bmap_add_extent_delay_real(
 		}
 		temp = xfs_bmap_worst_indlen(bma->ip, temp);
 		temp2 = xfs_bmap_worst_indlen(bma->ip, temp2);
-		diff = (int)(temp + temp2 - startblockval(PREV.br_startblock) -
-			(bma->cur ? bma->cur->bc_private.b.allocated : 0));
+		diff = (int)(temp + temp2 -
+			     (startblockval(PREV.br_startblock) -
+			      (bma->cur ?
+			       bma->cur->bc_private.b.allocated : 0)));
 		if (diff > 0) {
 			error = xfs_mod_fdblocks(bma->ip->i_mount,
 						 -((int64_t)diff), false);
@@ -2164,7 +2166,6 @@ xfs_bmap_add_extent_delay_real(
 		temp = da_new;
 		if (bma->cur)
 			temp += bma->cur->bc_private.b.allocated;
-		ASSERT(temp <= da_old);
 		if (temp < da_old)
 			xfs_mod_fdblocks(bma->ip->i_mount,
 					(int64_t)(da_old - temp), false);
-- 
2.11.0

[PATCH 15/23] xfs: BMAPX shouldn't barf on inline-format directories

[Christoph Hellwig]

From: "Darrick J. Wong" <darrick.wong@oracle.com>

commit 6eadbf4c8ba816c10d1c97bed9aa861d9fd17809 upstream.

When we're fulfilling a BMAPX request, jump out early if the data fork
is in local format.  This prevents us from hitting a debugging check in
bmapi_read and barfing errors back to userspace.  The on-disk extent
count check later isn't sufficient for IF_DELALLOC mode because da
extents are in memory and not on disk.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_bmap_util.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index cad4e3e2df00..9581e90fd559 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -583,9 +583,13 @@ xfs_getbmap(
 		}
 		break;
 	default:
+		/* Local format data forks report no extents. */
+		if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
+			bmv->bmv_entries = 0;
+			return 0;
+		}
 		if (ip->i_d.di_format != XFS_DINODE_FMT_EXTENTS &&
-		    ip->i_d.di_format != XFS_DINODE_FMT_BTREE &&
-		    ip->i_d.di_format != XFS_DINODE_FMT_LOCAL)
+		    ip->i_d.di_format != XFS_DINODE_FMT_BTREE)
 			return -EINVAL;
 
 		if (xfs_get_extsz_hint(ip) ||
-- 
2.11.0

[PATCH 16/23] xfs: bad assertion for delalloc an extent that start at i_size

[Christoph Hellwig]

From: Zorro Lang <zlang@redhat.com>

commit 892d2a5f705723b2cb488bfb38bcbdcf83273184 upstream.

By run fsstress long enough time enough in RHEL-7, I find an
assertion failure (harder to reproduce on linux-4.11, but problem
is still there):

  XFS: Assertion failed: (iflags & BMV_IF_DELALLOC) != 0, file: fs/xfs/xfs_bmap_util.c

The assertion is in xfs_getbmap() funciton:

  if (map[i].br_startblock == DELAYSTARTBLOCK &&
-->   map[i].br_startoff <= XFS_B_TO_FSB(mp, XFS_ISIZE(ip)))
          ASSERT((iflags & BMV_IF_DELALLOC) != 0);

When map[i].br_startoff == XFS_B_TO_FSB(mp, XFS_ISIZE(ip)), the
startoff is just at EOF. But we only need to make sure delalloc
extents that are within EOF, not include EOF.

Signed-off-by: Zorro Lang <zlang@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_bmap_util.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_bmap_util.c b/fs/xfs/xfs_bmap_util.c
index 9581e90fd559..70fbecbb2845 100644
--- a/fs/xfs/xfs_bmap_util.c
+++ b/fs/xfs/xfs_bmap_util.c
@@ -717,7 +717,7 @@ xfs_getbmap(
 			 * extents.
 			 */
 			if (map[i].br_startblock == DELAYSTARTBLOCK &&
-			    map[i].br_startoff <= XFS_B_TO_FSB(mp, XFS_ISIZE(ip)))
+			    map[i].br_startoff < XFS_B_TO_FSB(mp, XFS_ISIZE(ip)))
 				ASSERT((iflags & BMV_IF_DELALLOC) != 0);
 
                         if (map[i].br_startblock == HOLESTARTBLOCK &&
-- 
2.11.0

[PATCH 17/23] xfs: xfs_trans_alloc_empty

[Christoph Hellwig]

This is a partial cherry-pick of commit e89c041338
("xfs: implement the GETFSMAP ioctl"), which also adds this helper, and
a great example of why feature patches should be properly split into
their parts.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
[hch: split from the larger patch for -stable]
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_trans.c | 22 ++++++++++++++++++++++
 fs/xfs/xfs_trans.h |  2 ++
 2 files changed, 24 insertions(+)

diff --git a/fs/xfs/xfs_trans.c b/fs/xfs/xfs_trans.c
index 70f42ea86dfb..a280e126491f 100644
--- a/fs/xfs/xfs_trans.c
+++ b/fs/xfs/xfs_trans.c
@@ -263,6 +263,28 @@ xfs_trans_alloc(
 }
 
 /*
+ * Create an empty transaction with no reservation.  This is a defensive
+ * mechanism for routines that query metadata without actually modifying
+ * them -- if the metadata being queried is somehow cross-linked (think a
+ * btree block pointer that points higher in the tree), we risk deadlock.
+ * However, blocks grabbed as part of a transaction can be re-grabbed.
+ * The verifiers will notice the corrupt block and the operation will fail
+ * back to userspace without deadlocking.
+ *
+ * Note the zero-length reservation; this transaction MUST be cancelled
+ * without any dirty data.
+ */
+int
+xfs_trans_alloc_empty(
+	struct xfs_mount		*mp,
+	struct xfs_trans		**tpp)
+{
+	struct xfs_trans_res		resv = {0};
+
+	return xfs_trans_alloc(mp, &resv, 0, 0, XFS_TRANS_NO_WRITECOUNT, tpp);
+}
+
+/*
  * Record the indicated change to the given field for application
  * to the file system's superblock when the transaction commits.
  * For now, just store the change in the transaction structure.
diff --git a/fs/xfs/xfs_trans.h b/fs/xfs/xfs_trans.h
index 1646f659b60f..2a9292df6640 100644
--- a/fs/xfs/xfs_trans.h
+++ b/fs/xfs/xfs_trans.h
@@ -158,6 +158,8 @@ typedef struct xfs_trans {
 int		xfs_trans_alloc(struct xfs_mount *mp, struct xfs_trans_res *resp,
 			uint blocks, uint rtextents, uint flags,
 			struct xfs_trans **tpp);
+int		xfs_trans_alloc_empty(struct xfs_mount *mp,
+			struct xfs_trans **tpp);
 void		xfs_trans_mod_sb(xfs_trans_t *, uint, int64_t);
 
 struct xfs_buf	*xfs_trans_get_buf_map(struct xfs_trans *tp,
-- 
2.11.0

[PATCH 18/23] xfs: avoid mount-time deadlock in CoW extent recovery

[Christoph Hellwig]

From: "Darrick J. Wong" <darrick.wong@oracle.com>

commit 3ecb3ac7b950ff8f6c6a61e8b7b0d6e3546429a0 upstream.

If a malicious user corrupts the refcount btree to cause a cycle between
different levels of the tree, the next mount attempt will deadlock in
the CoW recovery routine while grabbing buffer locks.  We can use the
ability to re-grab a buffer that was previous locked to a transaction to
avoid deadlocks, so do that here.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
---
 fs/xfs/libxfs/xfs_refcount.c | 43 +++++++++++++++++++++++++++++++------------
 1 file changed, 31 insertions(+), 12 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_refcount.c b/fs/xfs/libxfs/xfs_refcount.c
index b177ef33cd4c..82a38d86ebad 100644
--- a/fs/xfs/libxfs/xfs_refcount.c
+++ b/fs/xfs/libxfs/xfs_refcount.c
@@ -1629,13 +1629,28 @@ xfs_refcount_recover_cow_leftovers(
 	if (mp->m_sb.sb_agblocks >= XFS_REFC_COW_START)
 		return -EOPNOTSUPP;
 
-	error = xfs_alloc_read_agf(mp, NULL, agno, 0, &agbp);
+	INIT_LIST_HEAD(&debris);
+
+	/*
+	 * In this first part, we use an empty transaction to gather up
+	 * all the leftover CoW extents so that we can subsequently
+	 * delete them.  The empty transaction is used to avoid
+	 * a buffer lock deadlock if there happens to be a loop in the
+	 * refcountbt because we're allowed to re-grab a buffer that is
+	 * already attached to our transaction.  When we're done
+	 * recording the CoW debris we cancel the (empty) transaction
+	 * and everything goes away cleanly.
+	 */
+	error = xfs_trans_alloc_empty(mp, &tp);
 	if (error)
 		return error;
-	cur = xfs_refcountbt_init_cursor(mp, NULL, agbp, agno, NULL);
+
+	error = xfs_alloc_read_agf(mp, tp, agno, 0, &agbp);
+	if (error)
+		goto out_trans;
+	cur = xfs_refcountbt_init_cursor(mp, tp, agbp, agno, NULL);
 
 	/* Find all the leftover CoW staging extents. */
-	INIT_LIST_HEAD(&debris);
 	memset(&low, 0, sizeof(low));
 	memset(&high, 0, sizeof(high));
 	low.rc.rc_startblock = XFS_REFC_COW_START;
@@ -1645,10 +1660,11 @@ xfs_refcount_recover_cow_leftovers(
 	if (error)
 		goto out_cursor;
 	xfs_btree_del_cursor(cur, XFS_BTREE_NOERROR);
-	xfs_buf_relse(agbp);
+	xfs_trans_brelse(tp, agbp);
+	xfs_trans_cancel(tp);
 
 	/* Now iterate the list to free the leftovers */
-	list_for_each_entry(rr, &debris, rr_list) {
+	list_for_each_entry_safe(rr, n, &debris, rr_list) {
 		/* Set up transaction. */
 		error = xfs_trans_alloc(mp, &M_RES(mp)->tr_write, 0, 0, 0, &tp);
 		if (error)
@@ -1676,8 +1692,16 @@ xfs_refcount_recover_cow_leftovers(
 		error = xfs_trans_commit(tp);
 		if (error)
 			goto out_free;
+
+		list_del(&rr->rr_list);
+		kmem_free(rr);
 	}
 
+	return error;
+out_defer:
+	xfs_defer_cancel(&dfops);
+out_trans:
+	xfs_trans_cancel(tp);
 out_free:
 	/* Free the leftover list */
 	list_for_each_entry_safe(rr, n, &debris, rr_list) {
@@ -1688,11 +1712,6 @@ xfs_refcount_recover_cow_leftovers(
 
 out_cursor:
 	xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
-	xfs_buf_relse(agbp);
-	goto out_free;
-
-out_defer:
-	xfs_defer_cancel(&dfops);
-	xfs_trans_cancel(tp);
-	goto out_free;
+	xfs_trans_brelse(tp, agbp);
+	goto out_trans;
 }
-- 
2.11.0

[PATCH 19/23] xfs: fix unaligned access in xfs_btree_visit_blocks

[Christoph Hellwig]

From: Eric Sandeen <sandeen@sandeen.net>

commit a4d768e702de224cc85e0c8eac9311763403b368 upstream.

This structure copy was throwing unaligned access warnings on sparc64:

Kernel unaligned access at TPC[1043c088] xfs_btree_visit_blocks+0x88/0xe0 [xfs]

xfs_btree_copy_ptrs does a memcpy, which avoids it.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/libxfs/xfs_btree.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/libxfs/xfs_btree.c b/fs/xfs/libxfs/xfs_btree.c
index c3decedc9455..3d0f96d159ff 100644
--- a/fs/xfs/libxfs/xfs_btree.c
+++ b/fs/xfs/libxfs/xfs_btree.c
@@ -4395,7 +4395,7 @@ xfs_btree_visit_blocks(
 			xfs_btree_readahead_ptr(cur, ptr, 1);
 
 			/* save for the next iteration of the loop */
-			lptr = *ptr;
+			xfs_btree_copy_ptrs(cur, &lptr, ptr, 1);
 		}
 
 		/* for each buffer in the level */
-- 
2.11.0

[PATCH 20/23] xfs: fix off-by-one on max nr_pages in xfs_find_get_desired_pgoff()

[Christoph Hellwig]

From: Eryu Guan <eguan@redhat.com>

commit 8affebe16d79ebefb1d9d6d56a46dc89716f9453 upstream.

xfs_find_get_desired_pgoff() is used to search for offset of hole or
data in page range [index, end] (both inclusive), and the max number
of pages to search should be at least one, if end == index.
Otherwise the only page is missed and no hole or data is found,
which is not correct.

When block size is smaller than page size, this can be demonstrated
by preallocating a file with size smaller than page size and writing
data to the last block. E.g. run this xfs_io command on a 1k block
size XFS on x86_64 host.

  # xfs_io -fc "falloc 0 3k" -c "pwrite 2k 1k" \
  	    -c "seek -d 0" /mnt/xfs/testfile
  wrote 1024/1024 bytes at offset 2048
  1 KiB, 1 ops; 0.0000 sec (33.675 MiB/sec and 34482.7586 ops/sec)
  Whence  Result
  DATA    EOF

Data at offset 2k was missed, and lseek(2) returned ENXIO.

This is uncovered by generic/285 subtest 07 and 08 on ppc64 host,
where pagesize is 64k. Because a recent change to generic/285
reduced the preallocated file size to smaller than 64k.

Signed-off-by: Eryu Guan <eguan@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index 35703a801372..aefa2134a8cb 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1049,7 +1049,7 @@ xfs_find_get_desired_pgoff(
 		unsigned	nr_pages;
 		unsigned int	i;
 
-		want = min_t(pgoff_t, end - index, PAGEVEC_SIZE);
+		want = min_t(pgoff_t, end - index, PAGEVEC_SIZE - 1) + 1;
 		nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index,
 					  want);
 		/*
-- 
2.11.0

[PATCH 21/23] xfs: Fix missed holes in SEEK_HOLE implementation

[Christoph Hellwig]

From: Jan Kara <jack@suse.cz>

commit 5375023ae1266553a7baa0845e82917d8803f48c upstream.

XFS SEEK_HOLE implementation could miss a hole in an unwritten extent as
can be seen by the following command:

xfs_io -c "falloc 0 256k" -c "pwrite 0 56k" -c "pwrite 128k 8k"
       -c "seek -h 0" file
wrote 57344/57344 bytes at offset 0
56 KiB, 14 ops; 0.0000 sec (49.312 MiB/sec and 12623.9856 ops/sec)
wrote 8192/8192 bytes at offset 131072
8 KiB, 2 ops; 0.0000 sec (70.383 MiB/sec and 18018.0180 ops/sec)
Whence	Result
HOLE	139264

Where we can see that hole at offset 56k was just ignored by SEEK_HOLE
implementation. The bug is in xfs_find_get_desired_pgoff() which does
not properly detect the case when pages are not contiguous.

Fix the problem by properly detecting when found page has larger offset
than expected.

CC: stable@vger.kernel.org
Fixes: d126d43f631f996daeee5006714fed914be32368
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_file.c | 29 +++++++++--------------------
 1 file changed, 9 insertions(+), 20 deletions(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index aefa2134a8cb..f1517e9928c7 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1076,17 +1076,6 @@ xfs_find_get_desired_pgoff(
 			break;
 		}
 
-		/*
-		 * At lease we found one page.  If this is the first time we
-		 * step into the loop, and if the first page index offset is
-		 * greater than the given search offset, a hole was found.
-		 */
-		if (type == HOLE_OFF && lastoff == startoff &&
-		    lastoff < page_offset(pvec.pages[0])) {
-			found = true;
-			break;
-		}
-
 		for (i = 0; i < nr_pages; i++) {
 			struct page	*page = pvec.pages[i];
 			loff_t		b_offset;
@@ -1098,18 +1087,18 @@ xfs_find_get_desired_pgoff(
 			 * file mapping. However, page->index will not change
 			 * because we have a reference on the page.
 			 *
-			 * Searching done if the page index is out of range.
-			 * If the current offset is not reaches the end of
-			 * the specified search range, there should be a hole
-			 * between them.
+			 * If current page offset is beyond where we've ended,
+			 * we've found a hole.
 			 */
-			if (page->index > end) {
-				if (type == HOLE_OFF && lastoff < endoff) {
-					*offset = lastoff;
-					found = true;
-				}
+			if (type == HOLE_OFF && lastoff < endoff &&
+			    lastoff < page_offset(pvec.pages[i])) {
+				found = true;
+				*offset = lastoff;
 				goto out;
 			}
+			/* Searching done if the page index is out of range. */
+			if (page->index > end)
+				goto out;
 
 			lock_page(page);
 			/*
-- 
2.11.0

[PATCH 22/23] xfs: Fix off-by-in in loop termination in xfs_find_get_desired_pgoff()

[Christoph Hellwig]

From: Jan Kara <jack@suse.cz>

commit d7fd24257aa60316bf81093f7f909dc9475ae974 upstream.

There is an off-by-one error in loop termination conditions in
xfs_find_get_desired_pgoff() since 'end' may index a page beyond end of
desired range if 'endoff' is page aligned. It doesn't have any visible
effects but still it is good to fix it.

Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/xfs/xfs_file.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index f1517e9928c7..dc0e4cb7029b 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1043,7 +1043,7 @@ xfs_find_get_desired_pgoff(
 
 	index = startoff >> PAGE_SHIFT;
 	endoff = XFS_FSB_TO_B(mp, map->br_startoff + map->br_blockcount);
-	end = endoff >> PAGE_SHIFT;
+	end = (endoff - 1) >> PAGE_SHIFT;
 	do {
 		int		want;
 		unsigned	nr_pages;
-- 
2.11.0

[PATCH 23/23] iomap_dio_rw: Prevent reading file data beyond iomap_dio->i_size

[Christoph Hellwig]

From: Chandan Rajendra <chandan@linux.vnet.ibm.com>

commit a008c31c7ef9a4106dbadf21b3bcb7e89826a5d7 upstream.

On a ppc64 machine executing overlayfs/019 with xfs as the lower and
upper filesystem causes the following call trace,

WARNING: CPU: 2 PID: 8034 at /root/repos/linux/fs/iomap.c:765 .iomap_dio_actor+0xcc/0x420
Modules linked in:
CPU: 2 PID: 8034 Comm: fsstress Tainted: G             L  4.11.0-rc5-next-20170405 #100
task: c000000631314880 task.stack: c0000003915d4000
NIP: c00000000035a72c LR: c00000000035a6f4 CTR: c00000000035a660
REGS: c0000003915d7570 TRAP: 0700   Tainted: G             L   (4.11.0-rc5-next-20170405)
MSR: 800000000282b032 <SF,VEC,VSX,EE,FP,ME,IR,DR,RI>
  CR: 24004284  XER: 00000000
CFAR: c0000000006f7190 SOFTE: 1
GPR00: c00000000035a6f4 c0000003915d77f0 c0000000015a3f00 000000007c22f600
GPR04: 000000000022d000 0000000000002600 c0000003b2d56360 c0000003915d7960
GPR08: c0000003915d7cd0 0000000000000002 0000000000002600 c000000000521cc0
GPR12: 0000000024004284 c00000000fd80a00 000000004b04ae64 ffffffffffffffff
GPR16: 000000001000ca70 0000000000000000 c0000003b2d56380 c00000000153d2b8
GPR20: 0000000000000010 c0000003bc87bac8 0000000000223000 000000000022f5ff
GPR24: c0000003b2d56360 000000000000000c 0000000000002600 000000000022d000
GPR28: 0000000000000000 c0000003915d7960 c0000003b2d56360 00000000000001ff
NIP [c00000000035a72c] .iomap_dio_actor+0xcc/0x420
LR [c00000000035a6f4] .iomap_dio_actor+0x94/0x420
Call Trace:
[c0000003915d77f0] [c00000000035a6f4] .iomap_dio_actor+0x94/0x420 (unreliable)
[c0000003915d78f0] [c00000000035b9f4] .iomap_apply+0xf4/0x1f0
[c0000003915d79d0] [c00000000035c320] .iomap_dio_rw+0x230/0x420
[c0000003915d7ae0] [c000000000512a14] .xfs_file_dio_aio_read+0x84/0x160
[c0000003915d7b80] [c000000000512d24] .xfs_file_read_iter+0x104/0x130
[c0000003915d7c10] [c0000000002d6234] .__vfs_read+0x114/0x1a0
[c0000003915d7cf0] [c0000000002d7a8c] .vfs_read+0xac/0x1a0
[c0000003915d7d90] [c0000000002d96b8] .SyS_read+0x58/0x100
[c0000003915d7e30] [c00000000000b8e0] system_call+0x38/0xfc
Instruction dump:
78630020 7f831b78 7ffc07b4 7c7ce039 40820360 a13d0018 2f890003 419e0288
2f890004 419e00a0 2f890001 419e02a8 <0fe00000> 3b80fffb 38210100 7f83e378

The above problem can also be recreated on a regular xfs filesystem
using the command,

$ fsstress -d /mnt -l 1000 -n 1000 -p 1000

The reason for the call trace is,
1. When 'reserving' blocks for delayed allocation , XFS reserves more
   blocks (i.e. past file's current EOF) than required. This is done
   because XFS assumes that userspace might write more data and hence
   'reserving' more blocks might lead to the file's new data being
   stored contiguously on disk.
2. The in-memory 'struct xfs_bmbt_irec' mapping the file's last extent would
   then cover the prealloc-ed EOF blocks in addition to the regular blocks.
3. When flushing the dirty blocks to disk, we only flush data till the
   file's EOF. But before writing out the dirty data, we allocate blocks
   on the disk for holding the file's new data. This allocation includes
   the blocks that are part of the 'prealloc EOF blocks'.
4. Later, when the last reference to the inode is being closed, XFS frees the
   unused 'prealloc EOF blocks' in xfs_inactive().

In step 3 above, When allocating space on disk for the delayed allocation
range, the space allocator might sometimes allocate less blocks than
required. If such an allocation ends right at the current EOF of the
file, We will not be able to clear the "delayed allocation" flag for the
'prealloc EOF blocks', since we won't have dirty buffer heads associated
with that range of the file.

In such a situation if a Direct I/O read operation is performed on file
range [X, Y] (where X < EOF and Y > EOF), we flush dirty data in the
range [X, Y] and invalidate page cache for that range (Refer to
iomap_dio_rw()). Later for performing the Direct I/O read, XFS obtains
the extent items (which are still cached in memory) for the file
range. When doing so we are not supposed to get an extent item with
IOMAP_DELALLOC flag set, since the previous "flush" operation should
have converted any delayed allocation data in the range [X, Y]. Hence we
end up hitting a WARN_ON_ONCE(1) statement in iomap_dio_actor().

This commit fixes the bug by preventing the read operation from going
beyond iomap_dio->i_size.

Reported-by: Santhosh G <santhog4@linux.vnet.ibm.com>
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
---
 fs/iomap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/iomap.c b/fs/iomap.c
index 1c25ae30500e..258fb4100b1d 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -909,6 +909,9 @@ iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter,
 			break;
 		}
 		pos += ret;
+
+		if (iov_iter_rw(iter) == READ && pos >= dio->i_size)
+			break;
 	} while ((count = iov_iter_count(iter)) > 0);
 	blk_finish_plug(&plug);
 
-- 
2.11.0

Re: 4.11-stable updates for XFS

[Greg KH]

On Sat, Jun 03, 2017 at 03:14:48PM +0200, Christoph Hellwig wrote:
> Hi all,
> 
> below are backports up to (almost) 4.12-rc4 for XFS.  I've selected all
> clear bugfixes for reported bugs.  One patch is a little odd as it's a
> subset of a patch that went into mainline, which included a bit of
> infrastructure in addition to the new feature, and we only need the
> infrastructure for stable.  Also a fs/iomap.c fix for code only used
> by XFS is included.

Thanks for these, and the 4.9 backports.  I've now queued them all up
and taken a few of them where needed, for 4.4 and 3.18-stable trees, for
those poor people still stuck with those kernels :)

thanks,

greg k-h

[PATCH 03/23] xfs: actually report xattr extents via iomap

[Christoph Hellwig]

From: "Darrick J. Wong" <darrick.wong@oracle.com>

commit 84358536dc355a9c8978ee425f87e116186bed16 upstream.

Apparently FIEMAP for xattrs has been broken since we switched to
the iomap backend because of an incorrect check for xattr presence.
Also fix the broken locking.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
 fs/xfs/xfs_iomap.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 288ee5b840d7..79e6dfac3dd6 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1170,10 +1170,10 @@ xfs_xattr_iomap_begin(
 	if (XFS_FORCED_SHUTDOWN(mp))
 		return -EIO;
 
-	lockmode = xfs_ilock_data_map_shared(ip);
+	lockmode = xfs_ilock_attr_map_shared(ip);
 
 	/* if there are no attribute fork or extents, return ENOENT */
-	if (XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) {
+	if (!XFS_IFORK_Q(ip) || !ip->i_d.di_anextents) {
 		error = -ENOENT;
 		goto out_unlock;
 	}
-- 
2.11.0