[XFS] Fix attr2 corruption with btree data extents

SGI-PV: 958747
SGI-Modid: xfs-linux-melb:xfs-kern:27792a

Signed-off-by: Barry Naujok <bnaujok@sgi.com>
Signed-off-by: Russell Cattelan <cattelan@thebarn.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

1 files changed, 42 insertions, 3 deletions

diff --git a/fs/xfs/xfs_attr_leaf.c b/fs/xfs/xfs_attr_leaf.c
index cc4ffa413da4..e4664136843d 100644
--- a/fs/xfs/xfs_attr_leaf.c
+++ b/fs/xfs/xfs_attr_leaf.c
@@ -150,6 +150,7 @@ xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes)
         int offset;
         int minforkoff; /* lower limit on valid forkoff locations */
         int maxforkoff; /* upper limit on valid forkoff locations */
+        int dsize;      
         xfs_mount_t *mp = dp->i_mount;
 
         offset = (XFS_LITINO(mp) - bytes) >> 3; /* rounded down */
@@ -169,8 +170,43 @@ xfs_attr_shortform_bytesfit(xfs_inode_t *dp, int bytes)
                 return 0;
         }
 
-        /* data fork btree root can have at least this many key/ptr pairs */
-        minforkoff = MAX(dp->i_df.if_bytes, XFS_BMDR_SPACE_CALC(MINDBTPTRS));
+        dsize = dp->i_df.if_bytes;
+        
+        switch (dp->i_d.di_format) {
+        case XFS_DINODE_FMT_EXTENTS:
+                /* 
+                 * If there is no attr fork and the data fork is extents, 
+                 * determine if creating the default attr fork will result 
+                 * in the extents form migrating to btree. If so, the 
+                 * minimum offset only needs to be the space required for 
+                 * the btree root.
+                 */ 
+                if (!dp->i_d.di_forkoff && dp->i_df.if_bytes > mp->m_attroffset)
+                        dsize = XFS_BMDR_SPACE_CALC(MINDBTPTRS);
+                break;
+                
+        case XFS_DINODE_FMT_BTREE:
+                /*
+                 * If have data btree then keep forkoff if we have one,
+                 * otherwise we are adding a new attr, so then we set 
+                 * minforkoff to where the btree root can finish so we have 
+                 * plenty of room for attrs
+                 */
+                if (dp->i_d.di_forkoff) {
+                        if (offset < dp->i_d.di_forkoff) 
+                                return 0;
+                        else 
+                                return dp->i_d.di_forkoff;
+                } else
+                        dsize = XFS_BMAP_BROOT_SPACE(dp->i_df.if_broot);
+                break;
+        }
+        
+        /* 
+         * A data fork btree root must have space for at least 
+         * MINDBTPTRS key/ptr pairs if the data fork is small or empty.
+         */
+        minforkoff = MAX(dsize, XFS_BMDR_SPACE_CALC(MINDBTPTRS));
         minforkoff = roundup(minforkoff, 8) >> 3;
 
         /* attr fork btree root can have at least this many key/ptr pairs */
@@ -336,7 +372,8 @@ xfs_attr_shortform_remove(xfs_da_args_t *args)
          */
         totsize -= size;
         if (totsize == sizeof(xfs_attr_sf_hdr_t) && !args->addname &&
-            (mp->m_flags & XFS_MOUNT_ATTR2)) {
+            (mp->m_flags & XFS_MOUNT_ATTR2) && 
+            (dp->i_d.di_format != XFS_DINODE_FMT_BTREE)) {
                 /*
                  * Last attribute now removed, revert to original
                  * inode format making all literal area available
@@ -748,6 +785,7 @@ xfs_attr_shortform_allfit(xfs_dabuf_t *bp, xfs_inode_t *dp)
                                 + be16_to_cpu(name_loc->valuelen);
         }
         if ((dp->i_mount->m_flags & XFS_MOUNT_ATTR2) &&
+            (dp->i_d.di_format != XFS_DINODE_FMT_BTREE) &&
             (bytes == sizeof(struct xfs_attr_sf_hdr)))
                 return(-1);
         return(xfs_attr_shortform_bytesfit(dp, bytes));
@@ -786,6 +824,7 @@ xfs_attr_leaf_to_shortform(xfs_dabuf_t *bp, xfs_da_args_t *args, int forkoff)
 
         if (forkoff == -1) {
                 ASSERT(dp->i_mount->m_flags & XFS_MOUNT_ATTR2);
+                ASSERT(dp->i_d.di_format != XFS_DINODE_FMT_BTREE);
 
                 /*
                  * Last attribute was removed, revert to original