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>

diff --git a/fs/fat/fat.h b/fs/fat/fat.h
index c517fc066cf7033aad86549f012e4e59c24e3722..413eaaf30ed57f68bcefc8bf4aa354df766a4e60 100644 (file)
--- a/fs/fat/fat.h
+++ b/fs/fat/fat.h
@@ -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 */

diff --git a/fs/fat/inode.c b/fs/fat/inode.c
index 27f49f4fa0d30a30cce3ae5e8cdb99439c6fc9f0..971ba7d549da4960032d43ae7d7e507a607a9874 100644 (file)
--- a/fs/fat/inode.c
+++ b/fs/fat/inode.c
@@ -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);
 

diff --git a/fs/fat/nfs.c b/fs/fat/nfs.c
index d59c02543a10ad9433924b41f680d78efdf06f15..0748196889b2591faf50abd922a26fcc330303d1 100644 (file)
--- a/fs/fat/nfs.c
+++ b/fs/fat/nfs.c
@@ -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;
-
-       if ((ino < MSDOS_ROOT_INO) || (ino == MSDOS_FSINFO_INO))
-               return NULL;
+       struct inode *inode = fat_ilookup(sb, ino, i_pos);
 
-       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;
 }