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authorDave Chinner <dchinner@redhat.com>2015-11-03 12:37:02 +1100
committerDave Chinner <david@fromorbit.com>2015-11-03 12:37:02 +1100
commit13ad4fe3e087ab66a140f1e00d98f28aa4e3bb28 (patch)
treee8f2cddd593803af2c6b8f6c31721ce7fe9d1fdb /fs/xfs
parent3af49285854df66260a263198cc15abb07b95287 (diff)
xfs: xfs_filemap_pmd_fault treats read faults as write faults
The code initially committed didn't have the same checks for write faults as the dax_pmd_fault code and hence treats all faults as write faults. We can get read faults through this path because they is no pmd_mkwrite path for write faults similar to the normal page fault path. Hence we need to ensure that we only do c/mtime updates on write faults, and freeze protection is unnecessary for read faults. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
Diffstat (limited to 'fs/xfs')
-rw-r--r--fs/xfs/xfs_file.c20
1 files changed, 16 insertions, 4 deletions
diff --git a/fs/xfs/xfs_file.c b/fs/xfs/xfs_file.c
index f429662d7d42..ce208e3896aa 100644
--- a/fs/xfs/xfs_file.c
+++ b/fs/xfs/xfs_file.c
@@ -1477,7 +1477,7 @@ xfs_file_llseek(
*
* mmap_sem (MM)
* sb_start_pagefault(vfs, freeze)
- * i_mmap_lock (XFS - truncate serialisation)
+ * i_mmaplock (XFS - truncate serialisation)
* page_lock (MM)
* i_lock (XFS - extent map serialisation)
*/
@@ -1545,6 +1545,13 @@ xfs_filemap_fault(
return ret;
}
+/*
+ * Similar to xfs_filemap_fault(), the DAX fault path can call into here on
+ * both read and write faults. Hence we need to handle both cases. There is no
+ * ->pmd_mkwrite callout for huge pages, so we have a single function here to
+ * handle both cases here. @flags carries the information on the type of fault
+ * occuring.
+ */
STATIC int
xfs_filemap_pmd_fault(
struct vm_area_struct *vma,
@@ -1561,13 +1568,18 @@ xfs_filemap_pmd_fault(
trace_xfs_filemap_pmd_fault(ip);
- sb_start_pagefault(inode->i_sb);
- file_update_time(vma->vm_file);
+ if (flags & FAULT_FLAG_WRITE) {
+ sb_start_pagefault(inode->i_sb);
+ file_update_time(vma->vm_file);
+ }
+
xfs_ilock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
ret = __dax_pmd_fault(vma, addr, pmd, flags, xfs_get_blocks_dax_fault,
NULL);
xfs_iunlock(XFS_I(inode), XFS_MMAPLOCK_SHARED);
- sb_end_pagefault(inode->i_sb);
+
+ if (flags & FAULT_FLAG_WRITE)
+ sb_end_pagefault(inode->i_sb);
return ret;
}