xfs: Check for extent overflow when adding/removing xattrs

Adding/removing an xattr can cause XFS_DA_NODE_MAXDEPTH extents to be
added. One extra extent for dabtree in case a local attr is large enough
to cause a double split.  It can also cause extent count to increase
proportional to the size of a remote xattr's value.

Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
index fd8e641..be51e70 100644 (file)
--- a/fs/xfs/libxfs/xfs_attr.c
+++ b/fs/xfs/libxfs/xfs_attr.c
@@ -396,6 +396,7 @@ xfs_attr_set(
        struct xfs_trans_res    tres;
        bool                    rsvd = (args->attr_filter & XFS_ATTR_ROOT);
        int                     error, local;
+       int                     rmt_blks = 0;
        unsigned int            total;
 
        if (XFS_FORCED_SHUTDOWN(dp->i_mount))
@@ -442,11 +443,15 @@ xfs_attr_set(
                tres.tr_logcount = XFS_ATTRSET_LOG_COUNT;
                tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
                total = args->total;
+
+               if (!local)
+                       rmt_blks = xfs_attr3_rmt_blocks(mp, args->valuelen);
        } else {
                XFS_STATS_INC(mp, xs_attr_remove);
 
                tres = M_RES(mp)->tr_attrrm;
                total = XFS_ATTRRM_SPACE_RES(mp);
+               rmt_blks = xfs_attr3_rmt_blocks(mp, XFS_XATTR_SIZE_MAX);
        }
 
        /*
@@ -460,6 +465,14 @@ xfs_attr_set(
 
        xfs_ilock(dp, XFS_ILOCK_EXCL);
        xfs_trans_ijoin(args->trans, dp, 0);
+
+       if (args->value || xfs_inode_hasattr(dp)) {
+               error = xfs_iext_count_may_overflow(dp, XFS_ATTR_FORK,
+                               XFS_IEXT_ATTR_MANIP_CNT(rmt_blks));
+               if (error)
+                       goto out_trans_cancel;
+       }
+
        if (args->value) {
                unsigned int    quota_flags = XFS_QMOPT_RES_REGBLKS;
 

diff --git a/fs/xfs/libxfs/xfs_inode_fork.h b/fs/xfs/libxfs/xfs_inode_fork.h
index ea1a9dd..8d89838 100644 (file)
--- a/fs/xfs/libxfs/xfs_inode_fork.h
+++ b/fs/xfs/libxfs/xfs_inode_fork.h
@@ -61,6 +61,16 @@ struct xfs_ifork {
        ((XFS_DA_NODE_MAXDEPTH + 1 + 1) * (mp)->m_dir_geo->fsbcount)
 
 /*
+ * Adding/removing an xattr can cause XFS_DA_NODE_MAXDEPTH extents to
+ * be added. One extra extent for dabtree in case a local attr is
+ * large enough to cause a double split.  It can also cause extent
+ * count to increase proportional to the size of a remote xattr's
+ * value.
+ */
+#define XFS_IEXT_ATTR_MANIP_CNT(rmt_blks) \
+       (XFS_DA_NODE_MAXDEPTH + max(1, rmt_blks))
+
+/*
  * Fork handling.
  */