xfs: apply rt extent alignment constraints to CoW extsize hint

The copy-on-write extent size hint is subject to the same alignment
constraints as the regular extent size hint.  Since we're in the process
of adding reflink (and therefore CoW) to the realtime device, we must
apply the same scattered rextsize alignment validation strategies to
both hints to deal with the possibility of rextsize changing.

Therefore, fix the inode validator to perform rextsize alignment checks
on regular realtime files, and to remove misaligned directory hints.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>

diff --git a/fs/xfs/libxfs/xfs_inode_buf.c b/fs/xfs/libxfs/xfs_inode_buf.c
index 1cc2622015071ae912dd26a40d4354197b17473e..dcb30ad521f05960138f4dec11af6f50b5a1cce1 100644 (file)
--- a/fs/xfs/libxfs/xfs_inode_buf.c
+++ b/fs/xfs/libxfs/xfs_inode_buf.c
@@ -912,11 +912,29 @@ xfs_inode_validate_cowextsize(
        bool                            rt_flag;
        bool                            hint_flag;
        uint32_t                        cowextsize_bytes;
+       uint32_t                        blocksize_bytes;
 
        rt_flag = (flags & XFS_DIFLAG_REALTIME);
        hint_flag = (flags2 & XFS_DIFLAG2_COWEXTSIZE);
        cowextsize_bytes = XFS_FSB_TO_B(mp, cowextsize);
 
+       /*
+        * Similar to extent size hints, a directory can be configured to
+        * propagate realtime status and a CoW extent size hint to newly
+        * created files even if there is no realtime device, and the hints on
+        * disk can become misaligned if the sysadmin changes the rt extent
+        * size while adding the realtime device.
+        *
+        * Therefore, we can only enforce the rextsize alignment check against
+        * regular realtime files, and rely on callers to decide when alignment
+        * checks are appropriate, and fix things up as needed.
+        */
+
+       if (rt_flag)
+               blocksize_bytes = XFS_FSB_TO_B(mp, mp->m_sb.sb_rextsize);
+       else
+               blocksize_bytes = mp->m_sb.sb_blocksize;
+
        if (hint_flag && !xfs_has_reflink(mp))
                return __this_address;
 
@@ -930,16 +948,13 @@ xfs_inode_validate_cowextsize(
        if (mode && !hint_flag && cowextsize != 0)
                return __this_address;
 
-       if (hint_flag && rt_flag)
-               return __this_address;
-
-       if (cowextsize_bytes % mp->m_sb.sb_blocksize)
+       if (cowextsize_bytes % blocksize_bytes)
                return __this_address;
 
        if (cowextsize > XFS_MAX_BMBT_EXTLEN)
                return __this_address;
 
-       if (cowextsize > mp->m_sb.sb_agblocks / 2)
+       if (!rt_flag && cowextsize > mp->m_sb.sb_agblocks / 2)
                return __this_address;
 
        return NULL;

diff --git a/fs/xfs/xfs_inode_item.c b/fs/xfs/xfs_inode_item.c
index 1275e8a35ea4fddedfc696e32f62492435d45511..5338c7fa12c972e6ca0c859678315534e5c7a0f4 100644 (file)
--- a/fs/xfs/xfs_inode_item.c
+++ b/fs/xfs/xfs_inode_item.c
@@ -157,6 +157,20 @@ xfs_inode_item_precommit(
        if (flags & XFS_ILOG_IVERSION)
                flags = ((flags & ~XFS_ILOG_IVERSION) | XFS_ILOG_CORE);
 
+       /*
+        * Inode verifiers do not check that the CoW extent size hint is an
+        * integer multiple of the rt extent size on a directory with both
+        * rtinherit and cowextsize 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_diflags2 & XFS_DIFLAG2_COWEXTSIZE) &&
+           xfs_extlen_to_rtxmod(ip->i_mount, ip->i_cowextsize) > 0) {
+               ip->i_diflags2 &= ~XFS_DIFLAG2_COWEXTSIZE;
+               ip->i_cowextsize = 0;
+               flags |= XFS_ILOG_CORE;
+       }
+
        if (!iip->ili_item.li_buf) {
                struct xfs_buf  *bp;
                int             error;

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 0ed2af0b1ff79159b6d38bbed944d9ea68c2d556..d621b270704c643ccf5994c1fe947b6519c1a528 100644 (file)
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -467,8 +467,21 @@ xfs_fill_fsxattr(
                }
        }
 
-       if (ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE)
-               fa->fsx_cowextsize = XFS_FSB_TO_B(mp, ip->i_cowextsize);
+       if (ip->i_diflags2 & XFS_DIFLAG2_COWEXTSIZE) {
+               /*
+                * Don't let a misaligned CoW extent size hint on a directory
+                * escape to userspace if it won't pass the setattr checks
+                * later.
+                */
+               if ((ip->i_diflags & XFS_DIFLAG_RTINHERIT) &&
+                   ip->i_cowextsize % mp->m_sb.sb_rextsize > 0) {
+                       fa->fsx_xflags &= ~FS_XFLAG_COWEXTSIZE;
+                       fa->fsx_cowextsize = 0;
+               } else {
+                       fa->fsx_cowextsize = XFS_FSB_TO_B(mp, ip->i_cowextsize);
+               }
+       }
+
        fa->fsx_projid = ip->i_projid;
        if (ifp && !xfs_need_iread_extents(ifp))
                fa->fsx_nextents = xfs_iext_count(ifp);