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Commit 8fceb4e0 authored by Namjae Jeon's avatar Namjae Jeon Committed by Linus Torvalds
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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: default avatarNamjae Jeon <namjae.jeon@samsung.com>
Signed-off-by: default avatarRavishankar N <ravi.n1@samsung.com>
Signed-off-by: default avatarAmit Sahrawat <a.sahrawat@samsung.com>
Acked-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ea3983ac

fs/fat/fat.h

+1 −0
Original line number Diff line number Diff line
@@ -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 */

fs/fat/inode.c

+15 −0
Original line number Diff line number Diff line
@@ -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);

fs/fat/nfs.c

+36 −5
Original line number Diff line number Diff line
@@ -50,19 +50,50 @@ static struct inode *fat_dget(struct super_block *sb, int i_logstart) 
	return inode;

}



static struct inode *__fat_nfs_get_inode(struct super_block *sb,

				       u64 ino, u32 generation, loff_t i_pos)

static struct inode *fat_ilookup(struct super_block *sb, u64 ino, loff_t i_pos)

{

	struct inode *inode;

	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 = 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;

}