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fat (exportfs): rebuild inode if ilookup() fails 

If the cache lookups fail,use the i_pos value to find the directory entry
of the inode and rebuild the inode.Since this involves accessing the FAT
media, do this only if the nostale_ro nfs mount option is specified.

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>
This commit is contained in:
Namjae Jeon 2013-04-29 16:21:12 -07:00 committed by Linus Torvalds
parent ea3983ace6
commit 8fceb4e017
3 changed files with 52 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
fs/fat/fat.h
View File

@ -75,6 +75,7 @@ struct msdos_sb_info {
unsigned long root_cluster; /* first cluster of the root directory */
unsigned long fsinfo_sector; /* sector number of FAT32 fsinfo */
struct mutex fat_lock;
struct mutex nfs_build_inode_lock;
struct mutex s_lock;
unsigned int prev_free; /* previously allocated cluster number */
unsigned int free_clusters; /* -1 if undefined */

15
fs/fat/inode.c
View File

@ -443,12 +443,25 @@ static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de)
return 0;
}
static inline void fat_lock_build_inode(struct msdos_sb_info *sbi)
{
if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
mutex_lock(&sbi->nfs_build_inode_lock);
}
static inline void fat_unlock_build_inode(struct msdos_sb_info *sbi)
{
if (sbi->options.nfs == FAT_NFS_NOSTALE_RO)
mutex_unlock(&sbi->nfs_build_inode_lock);
}
struct inode *fat_build_inode(struct super_block *sb,
struct msdos_dir_entry *de, loff_t i_pos)
{
struct inode *inode;
int err;
fat_lock_build_inode(MSDOS_SB(sb));
inode = fat_iget(sb, i_pos);
if (inode)
goto out;
@ -468,6 +481,7 @@ struct inode *fat_build_inode(struct super_block *sb,
fat_attach(inode, i_pos);
insert_inode_hash(inode);
out:
fat_unlock_build_inode(MSDOS_SB(sb));
return inode;
}
@ -1247,6 +1261,7 @@ int fat_fill_super(struct super_block *sb, void *data, int silent, int isvfat,
sb->s_magic = MSDOS_SUPER_MAGIC;
sb->s_op = &fat_sops;
sb->s_export_op = &fat_export_ops;
mutex_init(&sbi->nfs_build_inode_lock);
ratelimit_state_init(&sbi->ratelimit, DEFAULT_RATELIMIT_INTERVAL,
DEFAULT_RATELIMIT_BURST);

41
fs/fat/nfs.c
View File

@ -50,19 +50,50 @@ static struct inode *fat_dget(struct super_block *sb, int i_logstart)
return inode;
}
static struct inode *fat_ilookup(struct super_block *sb, u64 ino, loff_t i_pos)
{
if (MSDOS_SB(sb)->options.nfs == FAT_NFS_NOSTALE_RO)
return fat_iget(sb, i_pos);
else {
if ((ino < MSDOS_ROOT_INO) || (ino == MSDOS_FSINFO_INO))
return NULL;
return ilookup(sb, ino);
}
}
static struct inode *__fat_nfs_get_inode(struct super_block *sb,
u64 ino, u32 generation, loff_t i_pos)
{
struct inode *inode;
struct inode *inode = fat_ilookup(sb, ino, i_pos);
if ((ino < MSDOS_ROOT_INO) || (ino == MSDOS_FSINFO_INO))
return NULL;
inode = ilookup(sb, ino);
if (inode && generation && (inode->i_generation != generation)) {
iput(inode);
inode = NULL;
}
if (inode == NULL && MSDOS_SB(sb)->options.nfs == FAT_NFS_NOSTALE_RO) {
struct buffer_head *bh = NULL;
struct msdos_dir_entry *de ;
sector_t blocknr;
int offset;
fat_get_blknr_offset(MSDOS_SB(sb), i_pos, &blocknr, &offset);
bh = sb_bread(sb, blocknr);
if (!bh) {
fat_msg(sb, KERN_ERR,
"unable to read block(%llu) for building NFS inode",
(llu)blocknr);
return inode;
}
de = (struct msdos_dir_entry *)bh->b_data;
/* If a file is deleted on server and client is not updated
* yet, we must not build the inode upon a lookup call.
*/
if (IS_FREE(de[offset].name))
inode = NULL;
else
inode = fat_build_inode(sb, &de[offset], i_pos);
brelse(bh);
}
return inode;
}