1 files changed, 127 insertions, 32 deletions

diff --git a/fs/xfs/xfs_dfrag.c b/fs/xfs/xfs_dfrag.c
index d1483a4f71b8..5bba29a07812 100644
--- a/fs/xfs/xfs_dfrag.c
+++ b/fs/xfs/xfs_dfrag.c
@@ -45,15 +45,21 @@
 #include "xfs_vnodeops.h"
 #include "xfs_trace.h"
 
+
+static int xfs_swap_extents(
+        xfs_inode_t     *ip,    /* target inode */
+        xfs_inode_t     *tip,   /* tmp inode */
+        xfs_swapext_t   *sxp);
+
 /*
- * Syssgi interface for swapext
+ * ioctl interface for swapext
  */
 int
 xfs_swapext(
         xfs_swapext_t   *sxp)
 {
         xfs_inode_t     *ip, *tip;
-        struct file     *file, *target_file;
+        struct file     *file, *tmp_file;
         int             error = 0;
 
         /* Pull information for the target fd */
@@ -68,56 +74,138 @@ xfs_swapext(
                 goto out_put_file;
         }
 
-        target_file = fget((int)sxp->sx_fdtmp);
-        if (!target_file) {
+        tmp_file = fget((int)sxp->sx_fdtmp);
+        if (!tmp_file) {
                 error = XFS_ERROR(EINVAL);
                 goto out_put_file;
         }
 
-        if (!(target_file->f_mode & FMODE_WRITE) ||
-            (target_file->f_flags & O_APPEND)) {
+        if (!(tmp_file->f_mode & FMODE_WRITE) ||
+            (tmp_file->f_flags & O_APPEND)) {
                 error = XFS_ERROR(EBADF);
-                goto out_put_target_file;
+                goto out_put_tmp_file;
         }
 
         if (IS_SWAPFILE(file->f_path.dentry->d_inode) ||
-            IS_SWAPFILE(target_file->f_path.dentry->d_inode)) {
+            IS_SWAPFILE(tmp_file->f_path.dentry->d_inode)) {
                 error = XFS_ERROR(EINVAL);
-                goto out_put_target_file;
+                goto out_put_tmp_file;
         }
 
         ip = XFS_I(file->f_path.dentry->d_inode);
-        tip = XFS_I(target_file->f_path.dentry->d_inode);
+        tip = XFS_I(tmp_file->f_path.dentry->d_inode);
 
         if (ip->i_mount != tip->i_mount) {
                 error = XFS_ERROR(EINVAL);
-                goto out_put_target_file;
+                goto out_put_tmp_file;
         }
 
         if (ip->i_ino == tip->i_ino) {
                 error = XFS_ERROR(EINVAL);
-                goto out_put_target_file;
+                goto out_put_tmp_file;
         }
 
         if (XFS_FORCED_SHUTDOWN(ip->i_mount)) {
                 error = XFS_ERROR(EIO);
-                goto out_put_target_file;
+                goto out_put_tmp_file;
         }
 
         error = xfs_swap_extents(ip, tip, sxp);
 
- out_put_target_file:
-        fput(target_file);
+ out_put_tmp_file:
+        fput(tmp_file);
  out_put_file:
         fput(file);
  out:
         return error;
 }
 
-int
+/*
+ * We need to check that the format of the data fork in the temporary inode is
+ * valid for the target inode before doing the swap. This is not a problem with
+ * attr1 because of the fixed fork offset, but attr2 has a dynamically sized
+ * data fork depending on the space the attribute fork is taking so we can get
+ * invalid formats on the target inode.
+ *
+ * E.g. target has space for 7 extents in extent format, temp inode only has
+ * space for 6.  If we defragment down to 7 extents, then the tmp format is a
+ * btree, but when swapped it needs to be in extent format. Hence we can't just
+ * blindly swap data forks on attr2 filesystems.
+ *
+ * Note that we check the swap in both directions so that we don't end up with
+ * a corrupt temporary inode, either.
+ *
+ * Note that fixing the way xfs_fsr sets up the attribute fork in the source
+ * inode will prevent this situation from occurring, so all we do here is
+ * reject and log the attempt. basically we are putting the responsibility on
+ * userspace to get this right.
+ */
+static int
+xfs_swap_extents_check_format(
+        xfs_inode_t     *ip,    /* target inode */
+        xfs_inode_t     *tip)   /* tmp inode */
+{
+
+        /* Should never get a local format */
+        if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL ||
+            tip->i_d.di_format == XFS_DINODE_FMT_LOCAL)
+                return EINVAL;
+
+        /*
+         * if the target inode has less extents that then temporary inode then
+         * why did userspace call us?
+         */
+        if (ip->i_d.di_nextents < tip->i_d.di_nextents)
+                return EINVAL;
+
+        /*
+         * if the target inode is in extent form and the temp inode is in btree
+         * form then we will end up with the target inode in the wrong format
+         * as we already know there are less extents in the temp inode.
+         */
+        if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
+            tip->i_d.di_format == XFS_DINODE_FMT_BTREE)
+                return EINVAL;
+
+        /* Check temp in extent form to max in target */
+        if (tip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
+            XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) > ip->i_df.if_ext_max)
+                return EINVAL;
+
+        /* Check target in extent form to max in temp */
+        if (ip->i_d.di_format == XFS_DINODE_FMT_EXTENTS &&
+            XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) > tip->i_df.if_ext_max)
+                return EINVAL;
+
+        /*
+         * If we are in a btree format, check that the temp root block will fit
+         * in the target and that it has enough extents to be in btree format
+         * in the target.
+         *
+         * Note that we have to be careful to allow btree->extent conversions
+         * (a common defrag case) which will occur when the temp inode is in
+         * extent format...
+         */
+        if (tip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
+            ((XFS_IFORK_BOFF(ip) &&
+              tip->i_df.if_broot_bytes > XFS_IFORK_BOFF(ip)) ||
+             XFS_IFORK_NEXTENTS(tip, XFS_DATA_FORK) <= ip->i_df.if_ext_max))
+                return EINVAL;
+
+        /* Reciprocal target->temp btree format checks */
+        if (ip->i_d.di_format == XFS_DINODE_FMT_BTREE &&
+            ((XFS_IFORK_BOFF(tip) &&
+              ip->i_df.if_broot_bytes > XFS_IFORK_BOFF(tip)) ||
+             XFS_IFORK_NEXTENTS(ip, XFS_DATA_FORK) <= tip->i_df.if_ext_max))
+                return EINVAL;
+
+        return 0;
+}
+
+static int
 xfs_swap_extents(
-        xfs_inode_t     *ip,
-        xfs_inode_t     *tip,
+        xfs_inode_t     *ip,    /* target inode */
+        xfs_inode_t     *tip,   /* tmp inode */
         xfs_swapext_t   *sxp)
 {
         xfs_mount_t     *mp;
@@ -161,13 +249,6 @@ xfs_swap_extents(
                 goto out_unlock;
         }
 
-        /* Should never get a local format */
-        if (ip->i_d.di_format == XFS_DINODE_FMT_LOCAL ||
-            tip->i_d.di_format == XFS_DINODE_FMT_LOCAL) {
-                error = XFS_ERROR(EINVAL);
-                goto out_unlock;
-        }
-
         if (VN_CACHED(VFS_I(tip)) != 0) {
                 error = xfs_flushinval_pages(tip, 0, -1,
                                 FI_REMAPF_LOCKED);
@@ -189,13 +270,15 @@ xfs_swap_extents(
                 goto out_unlock;
         }
 
-        /*
-         * If the target has extended attributes, the tmp file
-         * must also in order to ensure the correct data fork
-         * format.
-         */
-        if ( XFS_IFORK_Q(ip) != XFS_IFORK_Q(tip) ) {
-                error = XFS_ERROR(EINVAL);
+        trace_xfs_swap_extent_before(ip, 0);
+        trace_xfs_swap_extent_before(tip, 1);
+
+        /* check inode formats now that data is flushed */
+        error = xfs_swap_extents_check_format(ip, tip);
+        if (error) {
+                xfs_fs_cmn_err(CE_NOTE, mp,
+                    "%s: inode 0x%llx format is incompatible for exchanging.",
+                                __FILE__, ip->i_ino);
                 goto out_unlock;
         }
 
@@ -276,6 +359,16 @@ xfs_swap_extents(
         *tifp = *tempifp;       /* struct copy */
 
         /*
+         * Fix the in-memory data fork values that are dependent on the fork
+         * offset in the inode. We can't assume they remain the same as attr2
+         * has dynamic fork offsets.
+         */
+        ifp->if_ext_max = XFS_IFORK_SIZE(ip, XFS_DATA_FORK) /
+                                        (uint)sizeof(xfs_bmbt_rec_t);
+        tifp->if_ext_max = XFS_IFORK_SIZE(tip, XFS_DATA_FORK) /
+                                        (uint)sizeof(xfs_bmbt_rec_t);
+
+        /*
          * Fix the on-disk inode values
          */
         tmp = (__uint64_t)ip->i_d.di_nblocks;
@@ -347,6 +440,8 @@ xfs_swap_extents(
 
         error = xfs_trans_commit(tp, XFS_TRANS_SWAPEXT);
 
+        trace_xfs_swap_extent_after(ip, 0);
+        trace_xfs_swap_extent_after(tip, 1);
 out:
         kmem_free(tempifp);
         return error;