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authorNamjae Jeon <namjae.jeon@samsung.com>2013-04-29 16:21:08 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-04-29 18:28:40 -0700
commit2628b7a6ac0d7d8246b6781a3e4489d78391ab54 (patch)
tree9befb3e857086352412a785ec779f4ea74bb845d /fs
parent35623715818dfa720cccf99cd280dcbb4b78da23 (diff)
downloadlinux-2628b7a6ac0d7d8246b6781a3e4489d78391ab54.tar.gz
fat: introduce 2 new values for the -o nfs mount option
This patchset eliminates the client side ESTALE errors when a FAT partition exported over NFS has its dentries evicted from the cache. The idea is to find the on-disk location_'i_pos' of the dirent of the inode that has been evicted and use it to rebuild the inode. This patch: Provide two possible values 'stale_rw' and 'nostale_ro' for the -o nfs mount option.The first one allows all file operations but does not reduce ESTALE errors on memory constrained systems. The second one eliminates ESTALE errors but mounts the filesystem as read-only. Not specifying a value defaults to 'stale_rw'. Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com> Signed-off-by: Ravishankar N <ravi.n1@samsung.com> Signed-off-by: Amit Sahrawat <a.sahrawat@samsung.com> Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/fat/fat.h7
-rw-r--r--fs/fat/inode.c23
2 files changed, 21 insertions, 9 deletions
diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index e9cc3f0d58e..a7b1d86b37c 100644
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -23,6 +23,9 @@
#define FAT_ERRORS_PANIC 2 /* panic on error */
#define FAT_ERRORS_RO 3 /* remount r/o on error */
+#define FAT_NFS_STALE_RW 1 /* NFS RW support, can cause ESTALE */
+#define FAT_NFS_NOSTALE_RO 2 /* NFS RO support, no ESTALE issue */
+
struct fat_mount_options {
kuid_t fs_uid;
kgid_t fs_gid;
@@ -34,6 +37,7 @@ struct fat_mount_options {
unsigned short shortname; /* flags for shortname display/create rule */
unsigned char name_check; /* r = relaxed, n = normal, s = strict */
unsigned char errors; /* On error: continue, panic, remount-ro */
+ unsigned char nfs; /* NFS support: nostale_ro, stale_rw */
unsigned short allow_utime;/* permission for setting the [am]time */
unsigned quiet:1, /* set = fake successful chmods and chowns */
showexec:1, /* set = only set x bit for com/exe/bat */
@@ -48,8 +52,7 @@ struct fat_mount_options {
usefree:1, /* Use free_clusters for FAT32 */
tz_set:1, /* Filesystem timestamps' offset set */
rodir:1, /* allow ATTR_RO for directory */
- discard:1, /* Issue discard requests on deletions */
- nfs:1; /* Do extra work needed for NFS export */
+ discard:1; /* Issue discard requests on deletions */
};
#define FAT_HASH_BITS 8
diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index acf6e479b44..93fbc8a7f09 100644
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -814,8 +814,6 @@ static int fat_show_options(struct seq_file *m, struct dentry *root)
seq_puts(m, ",usefree");
if (opts->quiet)
seq_puts(m, ",quiet");
- if (opts->nfs)
- seq_puts(m, ",nfs");
if (opts->showexec)
seq_puts(m, ",showexec");
if (opts->sys_immutable)
@@ -849,6 +847,10 @@ static int fat_show_options(struct seq_file *m, struct dentry *root)
seq_puts(m, ",errors=panic");
else
seq_puts(m, ",errors=remount-ro");
+ if (opts->nfs == FAT_NFS_NOSTALE_RO)
+ seq_puts(m, ",nfs=nostale_ro");
+ else if (opts->nfs)
+ seq_puts(m, ",nfs=stale_rw");
if (opts->discard)
seq_puts(m, ",discard");
@@ -865,7 +867,7 @@ enum {
Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes,
Opt_obsolete, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont,
Opt_err_panic, Opt_err_ro, Opt_discard, Opt_nfs, Opt_time_offset,
- Opt_err,
+ Opt_nfs_stale_rw, Opt_nfs_nostale_ro, Opt_err,
};
static const match_table_t fat_tokens = {
@@ -895,7 +897,9 @@ static const match_table_t fat_tokens = {
{Opt_err_panic, "errors=panic"},
{Opt_err_ro, "errors=remount-ro"},
{Opt_discard, "discard"},
- {Opt_nfs, "nfs"},
+ {Opt_nfs_stale_rw, "nfs"},
+ {Opt_nfs_stale_rw, "nfs=stale_rw"},
+ {Opt_nfs_nostale_ro, "nfs=nostale_ro"},
{Opt_obsolete, "conv=binary"},
{Opt_obsolete, "conv=text"},
{Opt_obsolete, "conv=auto"},
@@ -1092,6 +1096,12 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
case Opt_err_ro:
opts->errors = FAT_ERRORS_RO;
break;
+ case Opt_nfs_stale_rw:
+ opts->nfs = FAT_NFS_STALE_RW;
+ break;
+ case Opt_nfs_nostale_ro:
+ opts->nfs = FAT_NFS_NOSTALE_RO;
+ break;
/* msdos specific */
case Opt_dots:
@@ -1150,9 +1160,6 @@ static int parse_options(struct super_block *sb, char *options, int is_vfat,
case Opt_discard:
opts->discard = 1;
break;
- case Opt_nfs:
- opts->nfs = 1;
- break;
/* obsolete mount options */
case Opt_obsolete:
@@ -1183,6 +1190,8 @@ out:
opts->allow_utime = ~opts->fs_dmask & (S_IWGRP | S_IWOTH);
if (opts->unicode_xlate)
opts->utf8 = 0;
+ if (opts->nfs == FAT_NFS_NOSTALE_RO)
+ sb->s_flags |= MS_RDONLY;
return 0;
}