xfs: fix memory reclaim recursion deadlock on locked inode buffer

Calling into memory reclaim with a locked inode buffer can deadlock
if memory reclaim tries to lock the inode buffer during inode
teardown. Convert the relevant memory allocations to use KM_NOFS to
avoid this deadlock condition.

Reported-by: Peter Watkins <treestem@gmail.com>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Alex Elder <aelder@sgi.com>
Signed-off-by: Dave Chinner <david@fromorbit.com>

1 files changed, 11 insertions, 9 deletions

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index 5715a9d8bcd6..4a08c91dc976 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -422,7 +422,7 @@ xfs_iformat(
         if (!XFS_DFORK_Q(dip))
                 return 0;
         ASSERT(ip->i_afp == NULL);
-        ip->i_afp = kmem_zone_zalloc(xfs_ifork_zone, KM_SLEEP);
+        ip->i_afp = kmem_zone_zalloc(xfs_ifork_zone, KM_SLEEP | KM_NOFS);
         ip->i_afp->if_ext_max =
                 XFS_IFORK_ASIZE(ip) / (uint)sizeof(xfs_bmbt_rec_t);
         switch (dip->di_aformat) {
@@ -505,7 +505,7 @@ xfs_iformat_local(
                 ifp->if_u1.if_data = ifp->if_u2.if_inline_data;
         else {
                 real_size = roundup(size, 4);
-                ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP);
+                ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP | KM_NOFS);
         }
         ifp->if_bytes = size;
         ifp->if_real_bytes = real_size;
@@ -632,7 +632,7 @@ xfs_iformat_btree(
         }
 
         ifp->if_broot_bytes = size;
-        ifp->if_broot = kmem_alloc(size, KM_SLEEP);
+        ifp->if_broot = kmem_alloc(size, KM_SLEEP | KM_NOFS);
         ASSERT(ifp->if_broot != NULL);
         /*
          * Copy and convert from the on-disk structure
@@ -2191,7 +2191,7 @@ xfs_iroot_realloc(
                  */
                 if (ifp->if_broot_bytes == 0) {
                         new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(rec_diff);
-                        ifp->if_broot = kmem_alloc(new_size, KM_SLEEP);
+                        ifp->if_broot = kmem_alloc(new_size, KM_SLEEP | KM_NOFS);
                         ifp->if_broot_bytes = (int)new_size;
                         return;
                 }
@@ -2207,7 +2207,7 @@ xfs_iroot_realloc(
                 new_size = (size_t)XFS_BMAP_BROOT_SPACE_CALC(new_max);
                 ifp->if_broot = kmem_realloc(ifp->if_broot, new_size,
                                 (size_t)XFS_BMAP_BROOT_SPACE_CALC(cur_max), /* old size */
-                                KM_SLEEP);
+                                KM_SLEEP | KM_NOFS);
                 op = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
                                                      ifp->if_broot_bytes);
                 np = (char *)XFS_BMAP_BROOT_PTR_ADDR(mp, ifp->if_broot, 1,
@@ -2233,7 +2233,7 @@ xfs_iroot_realloc(
         else
                 new_size = 0;
         if (new_size > 0) {
-                new_broot = kmem_alloc(new_size, KM_SLEEP);
+                new_broot = kmem_alloc(new_size, KM_SLEEP | KM_NOFS);
                 /*
                  * First copy over the btree block header.
                  */
@@ -2337,7 +2337,8 @@ xfs_idata_realloc(
                 real_size = roundup(new_size, 4);
                 if (ifp->if_u1.if_data == NULL) {
                         ASSERT(ifp->if_real_bytes == 0);
-                        ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP);
+                        ifp->if_u1.if_data = kmem_alloc(real_size,
+                                                        KM_SLEEP | KM_NOFS);
                 } else if (ifp->if_u1.if_data != ifp->if_u2.if_inline_data) {
                         /*
                          * Only do the realloc if the underlying size
@@ -2348,11 +2349,12 @@ xfs_idata_realloc(
                                         kmem_realloc(ifp->if_u1.if_data,
                                                         real_size,
                                                         ifp->if_real_bytes,
-                                                        KM_SLEEP);
+                                                        KM_SLEEP | KM_NOFS);
                         }
                 } else {
                         ASSERT(ifp->if_real_bytes == 0);
-                        ifp->if_u1.if_data = kmem_alloc(real_size, KM_SLEEP);
+                        ifp->if_u1.if_data = kmem_alloc(real_size,
+                                                        KM_SLEEP | KM_NOFS);
                         memcpy(ifp->if_u1.if_data, ifp->if_u2.if_inline_data,
                                 ifp->if_bytes);
                 }