diff options
| -rw-r--r-- | fs/fat/Makefile | 2 | ||||
| -rw-r--r-- | fs/fat/fat.h | 22 | ||||
| -rw-r--r-- | fs/fat/inode.c | 130 | ||||
| -rw-r--r-- | fs/fat/nfs.c | 151 |
4 files changed, 174 insertions, 131 deletions
diff --git a/fs/fat/Makefile b/fs/fat/Makefile index e061903..964b634 100644 --- a/fs/fat/Makefile +++ b/fs/fat/Makefile @@ -6,6 +6,6 @@ obj-$(CONFIG_FAT_FS) += fat.o obj-$(CONFIG_VFAT_FS) += vfat.o obj-$(CONFIG_MSDOS_FS) += msdos.o -fat-y := cache.o dir.o fatent.o file.o inode.o misc.o +fat-y := cache.o dir.o fatent.o file.o inode.o misc.o nfs.o vfat-y := namei_vfat.o msdos-y := namei_msdos.o diff --git a/fs/fat/fat.h b/fs/fat/fat.h index 7d8e0dc..fb95939 100644 --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -341,6 +341,20 @@ extern int fat_fill_super(struct super_block *sb, void *data, int silent, extern int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2); +static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, + struct inode *inode) +{ + loff_t i_pos; +#if BITS_PER_LONG == 32 + spin_lock(&sbi->inode_hash_lock); +#endif + i_pos = MSDOS_I(inode)->i_pos; +#if BITS_PER_LONG == 32 + spin_unlock(&sbi->inode_hash_lock); +#endif + return i_pos; +} + /* fat/misc.c */ extern __printf(3, 4) __cold void __fat_fs_error(struct super_block *sb, int report, const char *fmt, ...); @@ -366,6 +380,14 @@ extern int fat_sync_bhs(struct buffer_head **bhs, int nr_bhs); int fat_cache_init(void); void fat_cache_destroy(void); +/* fat/nfs.c */ +struct fid; +extern int fat_encode_fh(struct inode *inode, __u32 *fh, int *lenp, + struct inode *parent); +extern struct dentry *fat_fh_to_dentry(struct super_block *sb, struct fid *fid, + int fh_len, int fh_type); +extern struct dentry *fat_get_parent(struct dentry *child_dir); + /* helper for printk */ typedef unsigned long long llu; diff --git a/fs/fat/inode.c b/fs/fat/inode.c index 4e5a6ac..169f6eb 100644 --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -562,20 +562,6 @@ static int fat_statfs(struct dentry *dentry, struct kstatfs *buf) return 0; } -static inline loff_t fat_i_pos_read(struct msdos_sb_info *sbi, - struct inode *inode) -{ - loff_t i_pos; -#if BITS_PER_LONG == 32 - spin_lock(&sbi->inode_hash_lock); -#endif - i_pos = MSDOS_I(inode)->i_pos; -#if BITS_PER_LONG == 32 - spin_unlock(&sbi->inode_hash_lock); -#endif - return i_pos; -} - static int __fat_write_inode(struct inode *inode, int wait) { struct super_block *sb = inode->i_sb; @@ -668,122 +654,6 @@ static const struct super_operations fat_sops = { .show_options = fat_show_options, }; -/* - * a FAT file handle with fhtype 3 is - * 0/ i_ino - for fast, reliable lookup if still in the cache - * 1/ i_generation - to see if i_ino is still valid - * bit 0 == 0 iff directory - * 2/ i_pos(8-39) - if ino has changed, but still in cache - * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos - * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc - * - * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum - * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits - * of i_logstart is used to store the directory entry offset. - */ - -static struct dentry *fat_fh_to_dentry(struct super_block *sb, - struct fid *fid, int fh_len, int fh_type) -{ - struct inode *inode = NULL; - u32 *fh = fid->raw; - - if (fh_len < 5 || fh_type != 3) - return NULL; - - inode = ilookup(sb, fh[0]); - if (!inode || inode->i_generation != fh[1]) { - if (inode) - iput(inode); - inode = NULL; - } - if (!inode) { - loff_t i_pos; - int i_logstart = fh[3] & 0x0fffffff; - - i_pos = (loff_t)fh[2] << 8; - i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); - - /* try 2 - see if i_pos is in F-d-c - * require i_logstart to be the same - * Will fail if you truncate and then re-write - */ - - inode = fat_iget(sb, i_pos); - if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { - iput(inode); - inode = NULL; - } - } - - /* - * For now, do nothing if the inode is not found. - * - * What we could do is: - * - * - follow the file starting at fh[4], and record the ".." entry, - * and the name of the fh[2] entry. - * - then follow the ".." file finding the next step up. - * - * This way we build a path to the root of the tree. If this works, we - * lookup the path and so get this inode into the cache. Finally try - * the fat_iget lookup again. If that fails, then we are totally out - * of luck. But all that is for another day - */ - return d_obtain_alias(inode); -} - -static int -fat_encode_fh(struct inode *inode, __u32 *fh, int *lenp, struct inode *parent) -{ - int len = *lenp; - struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); - loff_t i_pos; - - if (len < 5) { - *lenp = 5; - return 255; /* no room */ - } - - i_pos = fat_i_pos_read(sbi, inode); - *lenp = 5; - fh[0] = inode->i_ino; - fh[1] = inode->i_generation; - fh[2] = i_pos >> 8; - fh[3] = ((i_pos & 0xf0) << 24) | MSDOS_I(inode)->i_logstart; - fh[4] = (i_pos & 0x0f) << 28; - if (parent) - fh[4] |= MSDOS_I(parent)->i_logstart; - return 3; -} - -static struct dentry *fat_get_parent(struct dentry *child) -{ - struct super_block *sb = child->d_sb; - struct buffer_head *bh; - struct msdos_dir_entry *de; - loff_t i_pos; - struct dentry *parent; - struct inode *inode; - int err; - - lock_super(sb); - - err = fat_get_dotdot_entry(child->d_inode, &bh, &de, &i_pos); - if (err) { - parent = ERR_PTR(err); - goto out; - } - inode = fat_build_inode(sb, de, i_pos); - brelse(bh); - - parent = d_obtain_alias(inode); -out: - unlock_super(sb); - - return parent; -} - static const struct export_operations fat_export_ops = { .encode_fh = fat_encode_fh, .fh_to_dentry = fat_fh_to_dentry, diff --git a/fs/fat/nfs.c b/fs/fat/nfs.c new file mode 100644 index 0000000..21609a1 --- /dev/null +++ b/fs/fat/nfs.c @@ -0,0 +1,151 @@ +/* fs/fat/nfs.c + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#include <linux/exportfs.h> +#include "fat.h" + +/* + * a FAT file handle with fhtype 3 is + * 0/ i_ino - for fast, reliable lookup if still in the cache + * 1/ i_generation - to see if i_ino is still valid + * bit 0 == 0 iff directory + * 2/ i_pos(8-39) - if ino has changed, but still in cache + * 3/ i_pos(4-7)|i_logstart - to semi-verify inode found at i_pos + * 4/ i_pos(0-3)|parent->i_logstart - maybe used to hunt for the file on disc + * + * Hack for NFSv2: Maximum FAT entry number is 28bits and maximum + * i_pos is 40bits (blocknr(32) + dir offset(8)), so two 4bits + * of i_logstart is used to store the directory entry offset. + */ + +int +fat_encode_fh(struct inode *inode, __u32 *fh, int *lenp, struct inode *parent) +{ + int len = *lenp; + struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); + loff_t i_pos; + + if (len < 5) { + *lenp = 5; + return 255; /* no room */ + } + + i_pos = fat_i_pos_read(sbi, inode); + *lenp = 5; + fh[0] = inode->i_ino; + fh[1] = inode->i_generation; + fh[2] = i_pos >> 8; + fh[3] = ((i_pos & 0xf0) << 24) | MSDOS_I(inode)->i_logstart; + fh[4] = (i_pos & 0x0f) << 28; + if (parent) + fh[4] |= MSDOS_I(parent)->i_logstart; + return 3; +} + +static int fat_is_valid_fh(int fh_len, int fh_type) +{ + return ((fh_len >= 5) && (fh_type == 3)); +} + +/** + * Map a NFS file handle to a corresponding dentry. + * The dentry may or may not be connected to the filesystem root. + */ +struct dentry *fat_fh_to_dentry(struct super_block *sb, struct fid *fid, + int fh_len, int fh_type) +{ + struct inode *inode = NULL; + u32 *fh = fid->raw; + loff_t i_pos; + unsigned long i_ino; + __u32 i_generation; + int i_logstart; + + if (!fat_is_valid_fh(fh_len, fh_type)) + return NULL; + + i_ino = fh[0]; + i_generation = fh[1]; + i_logstart = fh[3] & 0x0fffffff; + + /* Try i_ino lookup first - fastest and most reliable */ + inode = ilookup(sb, i_ino); + if (inode && (inode->i_generation != i_generation)) { + iput(inode); + inode = NULL; + } + if (!inode) { + i_pos = (loff_t)fh[2] << 8; + i_pos |= ((fh[3] >> 24) & 0xf0) | (fh[4] >> 28); + + /* try 2 - see if i_pos is in F-d-c + * require i_logstart to be the same + * Will fail if you truncate and then re-write + */ + + inode = fat_iget(sb, i_pos); + if (inode && MSDOS_I(inode)->i_logstart != i_logstart) { + iput(inode); + inode = NULL; + } + } + + /* + * For now, do nothing if the inode is not found. + * + * What we could do is: + * + * - follow the file starting at fh[4], and record the ".." entry, + * and the name of the fh[2] entry. + * - then follow the ".." file finding the next step up. + * + * This way we build a path to the root of the tree. If this works, we + * lookup the path and so get this inode into the cache. Finally try + * the fat_iget lookup again. If that fails, then we are totally out + * of luck. But all that is for another day + */ + return d_obtain_alias(inode); +} + +/* + * Find the parent for a directory that is not currently connected to + * the filesystem root. + * + * On entry, the caller holds child_dir->d_inode->i_mutex. + */ +struct dentry *fat_get_parent(struct dentry *child_dir) +{ + struct super_block *sb = child_dir->d_sb; + struct buffer_head *bh = NULL; + struct msdos_dir_entry *de; + loff_t i_pos; + struct dentry *parent; + struct inode *inode; + int err; + + lock_super(sb); + + err = fat_get_dotdot_entry(child_dir->d_inode, &bh, &de, &i_pos); + if (err) { + parent = ERR_PTR(err); + goto out; + } + inode = fat_build_inode(sb, de, i_pos); + + parent = d_obtain_alias(inode); +out: + brelse(bh); + unlock_super(sb); + + return parent; +} |
