From: Namjae Jeon <namjae.j...@samsung.com>

update nfs option in filesystem/vfat.txt

Signed-off-by: Namjae Jeon <namjae.j...@samsung.com>
Signed-off-by: Ravishankar N <ravi...@samsung.com>
Signed-off-by: Amit Sahrawat <a.sahra...@samsung.com>
---
 Documentation/filesystems/vfat.txt |   23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/Documentation/filesystems/vfat.txt 
b/Documentation/filesystems/vfat.txt
index de1e6c4..d62f8e6 100644
--- a/Documentation/filesystems/vfat.txt
+++ b/Documentation/filesystems/vfat.txt
@@ -141,13 +141,26 @@ discard       -- If set, issues discard/TRIM commands to 
the block
                 device when blocks are freed. This is useful for SSD devices
                 and sparse/thinly-provisoned LUNs.
 
-nfs           -- This option maintains an index (cache) of directory
-                inodes by i_logstart which is used by the nfs-related code to
-                improve look-ups.
-
-                Enable this only if you want to export the FAT filesystem
+nfs= stale_rw|nostale_ro
+             -- Enable this only if you want to export the FAT filesystem
                 over NFS
 
+                stale_rw:This option maintains an index (cache) of directory
+                inodes by i_logstart which is used by the nfs-related code to
+                improve look-ups.Full file operations (read/write) over NFS is 
supported
+                but with cache eviction at NFS server, this could result in 
ESTALE issues.
+
+                nostale_ro:This option bases the inode number and filehandle 
on the on-disk
+                location of a file in the MS-DOS directory entry.This ensures 
that ESTALE
+                will not be returned after a file is evicted from the inode 
cache. However,
+                it means that operations such as rename, create and unlink 
could cause
+                filehandles that previously pointed at one file to point at a 
different file,
+                potentially causing data corruption. For this reason, this 
option also mounts
+                the filesystem readonly.
+
+                To maintain backward compatibility, '-o nfs' is also accepted, 
defaulting to
+                stale_rw
+
 <bool>: 0,1,yes,no,true,false
 
 TODO
-- 
1.7.9.5

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