Merge tag 'xfs-5.13-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fixes from Darrick Wong:
 "This week's pile mitigates some decades-old problems in how extent
  size hints interact with realtime volumes, fixes some failures in
  online shrink, and fixes a problem where directory and symlink
  shrinking on extremely fragmented filesystems could fail.

  The most user-notable change here is to point users at our (new) IRC
  channel on OFTC. Freedom isn't free, it costs folks like you and me;
  and if you don't kowtow, they'll expel everyone and take over your
  channel. (Ok, ok, that didn't fit the song lyrics...)

  Summary:

   - Fix a bug where unmapping operations end earlier than expected,
     which can cause chaos on multi-block directory and symlink shrink
     operations.

   - Fix an erroneous assert that can trigger if we try to transition a
     bmap structure from btree format to extents format with zero
     extents. This was exposed by xfs/538"

* tag 'xfs-5.13-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: bunmapi has unnecessary AG lock ordering issues
  xfs: btree format inode forks can have zero extents
  xfs: add new IRC channel to MAINTAINERS
  xfs: validate extsz hints against rt extent size when rtinherit is set
  xfs: standardize extent size hint validation
  xfs: check free AG space when making per-AG reservations

8 files changed, 140 insertions, 86 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index 3a2384e63486..43819c4a71b2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -20014,6 +20014,7 @@ F:	arch/x86/xen/*swiotlb*
 F:	drivers/xen/*swiotlb*
 
 XFS FILESYSTEM
+C:	irc://irc.oftc.net/xfs
 M:	Darrick J. Wong <djwong@kernel.org>
 M:	linux-xfs@vger.kernel.org
 L:	linux-xfs@vger.kernel.org
diff --git a/fs/xfs/libxfs/xfs_ag_resv.c b/fs/xfs/libxfs/xfs_ag_resv.c
index e32a1833d523..bbfea8022a3b 100644
--- a/fs/xfs/libxfs/xfs_ag_resv.c
+++ b/fs/xfs/libxfs/xfs_ag_resv.c
@@ -325,10 +325,22 @@ out:
 		error2 = xfs_alloc_pagf_init(mp, tp, pag->pag_agno, 0);
 		if (error2)
 			return error2;
-		ASSERT(xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved +
-		       xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <=
-		       pag->pagf_freeblks + pag->pagf_flcount);
+
+		/*
+		 * If there isn't enough space in the AG to satisfy the
+		 * reservation, let the caller know that there wasn't enough
+		 * space.  Callers are responsible for deciding what to do
+		 * next, since (in theory) we can stumble along with
+		 * insufficient reservation if data blocks are being freed to
+		 * replenish the AG's free space.
+		 */
+		if (!error &&
+		    xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved +
+		    xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved >
+		    pag->pagf_freeblks + pag->pagf_flcount)
+			error = -ENOSPC;
 	}
+
 	return error;
 }
 
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 7e3b9b01431e..a3e0e6f672d6 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -605,7 +605,6 @@ xfs_bmap_btree_to_extents(
 
 	ASSERT(cur);
 	ASSERT(whichfork != XFS_COW_FORK);
-	ASSERT(!xfs_need_iread_extents(ifp));
 	ASSERT(ifp->if_format == XFS_DINODE_FMT_BTREE);
 	ASSERT(be16_to_cpu(rblock->bb_level) == 1);
 	ASSERT(be16_to_cpu(rblock->bb_numrecs) == 1);
@@ -5350,7 +5349,6 @@ __xfs_bunmapi(
 	xfs_fsblock_t		sum;
 	xfs_filblks_t		len = *rlen;	/* length to unmap in file */
 	xfs_fileoff_t		max_len;
-	xfs_agnumber_t		prev_agno = NULLAGNUMBER, agno;
 	xfs_fileoff_t		end;
 	struct xfs_iext_cursor	icur;
 	bool			done = false;
@@ -5442,16 +5440,6 @@ __xfs_bunmapi(
 		del = got;
 		wasdel = isnullstartblock(del.br_startblock);
 
-		/*
-		 * Make sure we don't touch multiple AGF headers out of order
-		 * in a single transaction, as that could cause AB-BA deadlocks.
-		 */
-		if (!wasdel && !isrt) {
-			agno = XFS_FSB_TO_AGNO(mp, del.br_startblock);
-			if (prev_agno != NULLAGNUMBER && prev_agno > agno)
-				break;
-			prev_agno = agno;
-		}
 		if (got.br_startoff < start) {
 			del.br_startoff = start;
 			del.br_blockcount -= start - got.br_startoff;
diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 5c9a7440d9e4..f3254a4f4cb4 100644
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -559,8 +559,17 @@ xfs_dinode_calc_crc(
 /*
  * Validate di_extsize hint.
  *
- * The rules are documented at xfs_ioctl_setattr_check_extsize().
- * These functions must be kept in sync with each other.
+ * 1. Extent size hint is only valid for directories and regular files.
+ * 2. FS_XFLAG_EXTSIZE is only valid for regular files.
+ * 3. FS_XFLAG_EXTSZINHERIT is only valid for directories.
+ * 4. Hint cannot be larger than MAXTEXTLEN.
+ * 5. Can be changed on directories at any time.
+ * 6. Hint value of 0 turns off hints, clears inode flags.
+ * 7. Extent size must be a multiple of the appropriate block size.
+ *    For realtime files, this is the rt extent size.
+ * 8. For non-realtime files, the extent size hint must be limited
+ *    to half the AG size to avoid alignment extending the extent beyond the
+ *    limits of the AG.
  */
 xfs_failaddr_t
 xfs_inode_validate_extsize(
@@ -580,6 +589,28 @@ xfs_inode_validate_extsize(
 	inherit_flag = (flags & XFS_DIFLAG_EXTSZINHERIT);
 	extsize_bytes = XFS_FSB_TO_B(mp, extsize);
 
+	/*
+	 * This comment describes a historic gap in this verifier function.
+	 *
+	 * On older kernels, the extent size hint verifier doesn't check that
+	 * the extent size hint is an integer multiple of the realtime extent
+	 * size on a directory with both RTINHERIT and EXTSZINHERIT flags set.
+	 * The verifier has always enforced the alignment rule for regular
+	 * files with the REALTIME flag set.
+	 *
+	 * If a directory with a misaligned extent size hint is allowed to
+	 * propagate that hint into a new regular realtime file, the result
+	 * is that the inode cluster buffer verifier will trigger a corruption
+	 * shutdown the next time it is run.
+	 *
+	 * Unfortunately, there could be filesystems with these misconfigured
+	 * directories in the wild, so we cannot add a check to this verifier
+	 * at this time because that will result a new source of directory
+	 * corruption errors when reading an existing filesystem.  Instead, we
+	 * permit the misconfiguration to pass through the verifiers so that
+	 * callers of this function can correct and mitigate externally.
+	 */
+
 	if (rt_flag)
 		blocksize_bytes = mp->m_sb.sb_rextsize << mp->m_sb.sb_blocklog;
 	else
@@ -616,8 +647,15 @@ xfs_inode_validate_extsize(
 /*
  * Validate di_cowextsize hint.
  *
- * The rules are documented at xfs_ioctl_setattr_check_cowextsize().
- * These functions must be kept in sync with each other.
+ * 1. CoW extent size hint can only be set if reflink is enabled on the fs.
+ *    The inode does not have to have any shared blocks, but it must be a v3.
+ * 2. FS_XFLAG_COWEXTSIZE is only valid for directories and regular files;
+ *    for a directory, the hint is propagated to new files.
+ * 3. Can be changed on files & directories at any time.
+ * 4. Hint value of 0 turns off hints, clears inode flags.
+ * 5. Extent size must be a multiple of the appropriate block size.
+ * 6. The extent size hint must be limited to half the AG size to avoid
+ *    alignment extending the extent beyond the limits of the AG.
  */
 xfs_failaddr_t
 xfs_inode_validate_cowextsize(
diff --git a/fs/xfs/libxfs/xfs_trans_inode.c b/fs/xfs/libxfs/xfs_trans_inode.c
index 78324e043e25..8d595a5c4abd 100644
--- a/fs/xfs/libxfs/xfs_trans_inode.c
+++ b/fs/xfs/libxfs/xfs_trans_inode.c
@@ -143,6 +143,23 @@ xfs_trans_log_inode(
 	}
 
 	/*
+	 * Inode verifiers on older kernels don't check that the extent size
+	 * hint is an integer multiple of the rt extent size on a directory
+	 * with both rtinherit and extszinherit flags set.  If we're logging a
+	 * directory that is misconfigured in this way, clear the hint.
+	 */
+	if ((ip->i_diflags & XFS_DIFLAG_RTINHERIT) &&
+	    (ip->i_diflags & XFS_DIFLAG_EXTSZINHERIT) &&
+	    (ip->i_extsize % ip->i_mount->m_sb.sb_rextsize) > 0) {
+		xfs_info_once(ip->i_mount,
+	"Correcting misaligned extent size hint in inode 0x%llx.", ip->i_ino);
+		ip->i_diflags &= ~(XFS_DIFLAG_EXTSIZE |
+				   XFS_DIFLAG_EXTSZINHERIT);
+		ip->i_extsize = 0;
+		flags |= XFS_ILOG_CORE;
+	}
+
+	/*
 	 * Record the specific change for fdatasync optimisation. This allows
 	 * fdatasync to skip log forces for inodes that are only timestamp
 	 * dirty.
diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 0369eb22c1bb..e4c2da4566f1 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -690,6 +690,7 @@ xfs_inode_inherit_flags(
 	const struct xfs_inode	*pip)
 {
 	unsigned int		di_flags = 0;
+	xfs_failaddr_t		failaddr;
 	umode_t			mode = VFS_I(ip)->i_mode;
 
 	if (S_ISDIR(mode)) {
@@ -729,6 +730,24 @@ xfs_inode_inherit_flags(
 		di_flags |= XFS_DIFLAG_FILESTREAM;
 
 	ip->i_diflags |= di_flags;
+
+	/*
+	 * Inode verifiers on older kernels only check that the extent size
+	 * hint is an integer multiple of the rt extent size on realtime files.
+	 * They did not check the hint alignment on a directory with both
+	 * rtinherit and extszinherit flags set.  If the misaligned hint is
+	 * propagated from a directory into a new realtime file, new file
+	 * allocations will fail due to math errors in the rt allocator and/or
+	 * trip the verifiers.  Validate the hint settings in the new file so
+	 * that we don't let broken hints propagate.
+	 */
+	failaddr = xfs_inode_validate_extsize(ip->i_mount, ip->i_extsize,
+			VFS_I(ip)->i_mode, ip->i_diflags);
+	if (failaddr) {
+		ip->i_diflags &= ~(XFS_DIFLAG_EXTSIZE |
+				   XFS_DIFLAG_EXTSZINHERIT);
+		ip->i_extsize = 0;
+	}
 }
 
 /* Propagate di_flags2 from a parent inode to a child inode. */
@@ -737,12 +756,22 @@ xfs_inode_inherit_flags2(
 	struct xfs_inode	*ip,
 	const struct xfs_inode	*pip)
 {
+	xfs_failaddr_t		failaddr;
+
 	if (pip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE) {
 		ip->i_diflags2 |= XFS_DIFLAG2_COWEXTSIZE;
 		ip->i_cowextsize = pip->i_cowextsize;
 	}
 	if (pip->i_diflags2 & XFS_DIFLAG2_DAX)
 		ip->i_diflags2 |= XFS_DIFLAG2_DAX;
+
+	/* Don't let invalid cowextsize hints propagate. */
+	failaddr = xfs_inode_validate_cowextsize(ip->i_mount, ip->i_cowextsize,
+			VFS_I(ip)->i_mode, ip->i_diflags, ip->i_diflags2);
+	if (failaddr) {
+		ip->i_diflags2 &= ~XFS_DIFLAG2_COWEXTSIZE;
+		ip->i_cowextsize = 0;
+	}
 }
 
 /*
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 3925bfcb2365..1fe4c1fc0aea 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1267,20 +1267,8 @@ out_error:
 }
 
 /*
- * extent size hint validation is somewhat cumbersome. Rules are:
- *
- * 1. extent size hint is only valid for directories and regular files
- * 2. FS_XFLAG_EXTSIZE is only valid for regular files
- * 3. FS_XFLAG_EXTSZINHERIT is only valid for directories.
- * 4. can only be changed on regular files if no extents are allocated
- * 5. can be changed on directories at any time
- * 6. extsize hint of 0 turns off hints, clears inode flags.
- * 7. Extent size must be a multiple of the appropriate block size.
- * 8. for non-realtime files, the extent size hint must be limited
- *    to half the AG size to avoid alignment extending the extent beyond the
- *    limits of the AG.
- *
- * Please keep this function in sync with xfs_scrub_inode_extsize.
+ * Validate a proposed extent size hint.  For regular files, the hint can only
+ * be changed if no extents are allocated.
  */
 static int
 xfs_ioctl_setattr_check_extsize(
@@ -1288,86 +1276,65 @@ xfs_ioctl_setattr_check_extsize(
 	struct fileattr		*fa)
 {
 	struct xfs_mount	*mp = ip->i_mount;
-	xfs_extlen_t		size;
-	xfs_fsblock_t		extsize_fsb;
+	xfs_failaddr_t		failaddr;
+	uint16_t		new_diflags;
 
 	if (!fa->fsx_valid)
 		return 0;
 
 	if (S_ISREG(VFS_I(ip)->i_mode) && ip->i_df.if_nextents &&
-	    ((ip->i_extsize << mp->m_sb.sb_blocklog) != fa->fsx_extsize))
+	    XFS_FSB_TO_B(mp, ip->i_extsize) != fa->fsx_extsize)
 		return -EINVAL;
 
-	if (fa->fsx_extsize == 0)
-		return 0;
-
-	extsize_fsb = XFS_B_TO_FSB(mp, fa->fsx_extsize);
-	if (extsize_fsb > MAXEXTLEN)
+	if (fa->fsx_extsize & mp->m_blockmask)
 		return -EINVAL;
 
-	if (XFS_IS_REALTIME_INODE(ip) ||
-	    (fa->fsx_xflags & FS_XFLAG_REALTIME)) {
-		size = mp->m_sb.sb_rextsize << mp->m_sb.sb_blocklog;
-	} else {
-		size = mp->m_sb.sb_blocksize;
-		if (extsize_fsb > mp->m_sb.sb_agblocks / 2)
+	new_diflags = xfs_flags2diflags(ip, fa->fsx_xflags);
+
+	/*
+	 * Inode verifiers on older kernels don't check that the extent size
+	 * hint is an integer multiple of the rt extent size on a directory
+	 * with both rtinherit and extszinherit flags set.  Don't let sysadmins
+	 * misconfigure directories.
+	 */
+	if ((new_diflags & XFS_DIFLAG_RTINHERIT) &&
+	    (new_diflags & XFS_DIFLAG_EXTSZINHERIT)) {
+		unsigned int	rtextsize_bytes;
+
+		rtextsize_bytes = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize);
+		if (fa->fsx_extsize % rtextsize_bytes)
 			return -EINVAL;
 	}
 
-	if (fa->fsx_extsize % size)
-		return -EINVAL;
-
-	return 0;
+	failaddr = xfs_inode_validate_extsize(ip->i_mount,
+			XFS_B_TO_FSB(mp, fa->fsx_extsize),
+			VFS_I(ip)->i_mode, new_diflags);
+	return failaddr != NULL ? -EINVAL : 0;
 }
 
-/*
- * CoW extent size hint validation rules are:
- *
- * 1. CoW extent size hint can only be set if reflink is enabled on the fs.
- *    The inode does not have to have any shared blocks, but it must be a v3.
- * 2. FS_XFLAG_COWEXTSIZE is only valid for directories and regular files;
- *    for a directory, the hint is propagated to new files.
- * 3. Can be changed on files & directories at any time.
- * 4. CoW extsize hint of 0 turns off hints, clears inode flags.
- * 5. Extent size must be a multiple of the appropriate block size.
- * 6. The extent size hint must be limited to half the AG size to avoid
- *    alignment extending the extent beyond the limits of the AG.
- *
- * Please keep this function in sync with xfs_scrub_inode_cowextsize.
- */
 static int
 xfs_ioctl_setattr_check_cowextsize(
 	struct xfs_inode	*ip,
 	struct fileattr		*fa)
 {
 	struct xfs_mount	*mp = ip->i_mount;
-	xfs_extlen_t		size;
-	xfs_fsblock_t		cowextsize_fsb;
+	xfs_failaddr_t		failaddr;
+	uint64_t		new_diflags2;
+	uint16_t		new_diflags;
 
 	if (!fa->fsx_valid)
 		return 0;
 
-	if (!(fa->fsx_xflags & FS_XFLAG_COWEXTSIZE))
-		return 0;
-
-	if (!xfs_sb_version_hasreflink(&ip->i_mount->m_sb))
+	if (fa->fsx_cowextsize & mp->m_blockmask)
 		return -EINVAL;
 
-	if (fa->fsx_cowextsize == 0)
-		return 0;
+	new_diflags = xfs_flags2diflags(ip, fa->fsx_xflags);
+	new_diflags2 = xfs_flags2diflags2(ip, fa->fsx_xflags);
 
-	cowextsize_fsb = XFS_B_TO_FSB(mp, fa->fsx_cowextsize);
-	if (cowextsize_fsb > MAXEXTLEN)
-		return -EINVAL;
-
-	size = mp->m_sb.sb_blocksize;
-	if (cowextsize_fsb > mp->m_sb.sb_agblocks / 2)
-		return -EINVAL;
-
-	if (fa->fsx_cowextsize % size)
-		return -EINVAL;
-
-	return 0;
+	failaddr = xfs_inode_validate_cowextsize(ip->i_mount,
+			XFS_B_TO_FSB(mp, fa->fsx_cowextsize),
+			VFS_I(ip)->i_mode, new_diflags, new_diflags2);
+	return failaddr != NULL ? -EINVAL : 0;
 }
 
 static int
diff --git a/fs/xfs/xfs_message.h b/fs/xfs/xfs_message.h
index 3c392b1512ac..7ec1a9207517 100644
--- a/fs/xfs/xfs_message.h
+++ b/fs/xfs/xfs_message.h
@@ -73,6 +73,8 @@ do {									\
 	xfs_printk_once(xfs_warn, dev, fmt, ##__VA_ARGS__)
 #define xfs_notice_once(dev, fmt, ...)				\
 	xfs_printk_once(xfs_notice, dev, fmt, ##__VA_ARGS__)
+#define xfs_info_once(dev, fmt, ...)				\
+	xfs_printk_once(xfs_info, dev, fmt, ##__VA_ARGS__)
 
 void assfail(struct xfs_mount *mp, char *expr, char *f, int l);
 void asswarn(struct xfs_mount *mp, char *expr, char *f, int l);