2013/1/20, OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx>: > Namjae Jeon <linkinjeon@xxxxxxxxx> writes: > >> We rewrite patch as your suggestion using dummy inode. Would please >> you review below patch code ? > > Looks like good as initial. Clean and shorter. > > Next is, we have to think about race. I.e. if real inode was made, what > happens? Is there no race? Hi OGAWA. Although checking several routines to check hang case you said, I didn't find anything. And There is no any race on test result also. Am I missing something ? Let me know your opinion. Thanks. > > Thanks. > >> Subject: [PATCH] fat (exportfs): rebuild directory-inode if fat_dget() >> fails >> >> This patch enables rebuilding of directory inodes which are not present >> in the cache.This is done by traversing the disk clusters to find the >> directory entry of the parent directory and using its i_pos to build the >> inode. >> >> Do this only if the "nostale_ro" nfs mount option is specified. >> >> --- >> fs/fat/dir.c | 23 +++++++++++++++++++++++ >> fs/fat/fat.h | 3 +++ >> fs/fat/inode.c | 2 +- >> fs/fat/nfs.c | 52 >> +++++++++++++++++++++++++++++++++++++++++++++++++++- >> 4 files changed, 78 insertions(+), 2 deletions(-) >> >> diff --git a/fs/fat/dir.c b/fs/fat/dir.c >> index 695c15c..ac97f34 100644 >> --- a/fs/fat/dir.c >> +++ b/fs/fat/dir.c >> @@ -975,6 +975,29 @@ int fat_scan(struct inode *dir, const unsigned char >> *name, >> >> EXPORT_SYMBOL_GPL(fat_scan); >> >> +/* >> + * Scans a directory for a given logstart. >> + * Returns an error code or zero. >> + */ >> +int fat_scan_logstart(struct inode *dir, int i_logstart, >> + struct fat_slot_info *sinfo) >> +{ >> + struct super_block *sb = dir->i_sb; >> + >> + sinfo->slot_off = 0; >> + sinfo->bh = NULL; >> + while (fat_get_short_entry(dir, &sinfo->slot_off, &sinfo->bh, >> + &sinfo->de) >= 0) { >> + if (fat_get_start(MSDOS_SB(sb), sinfo->de) == i_logstart) { >> + sinfo->slot_off -= sizeof(*sinfo->de); >> + sinfo->nr_slots = 1; >> + sinfo->i_pos = fat_make_i_pos(sb, sinfo->bh, sinfo->de); >> + return 0; >> + } >> + } >> + return -ENOENT; >> +} >> + >> static int __fat_remove_entries(struct inode *dir, loff_t pos, int >> nr_slots) >> { >> struct super_block *sb = dir->i_sb; >> diff --git a/fs/fat/fat.h b/fs/fat/fat.h >> index 73f15b8..d882c01 100644 >> --- a/fs/fat/fat.h >> +++ b/fs/fat/fat.h >> @@ -291,6 +291,8 @@ extern int fat_dir_empty(struct inode *dir); >> extern int fat_subdirs(struct inode *dir); >> extern int fat_scan(struct inode *dir, const unsigned char *name, >> struct fat_slot_info *sinfo); >> +extern int fat_scan_logstart(struct inode *dir, int i_logstart, >> + struct fat_slot_info *sinfo); >> extern int fat_get_dotdot_entry(struct inode *dir, struct buffer_head >> **bh, >> struct msdos_dir_entry **de); >> extern int fat_alloc_new_dir(struct inode *dir, struct timespec *ts); >> @@ -370,6 +372,7 @@ 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); >> +extern int fat_fill_inode(struct inode *inode, struct msdos_dir_entry >> *de); >> static inline unsigned long fat_dir_hash(int logstart) >> { >> return hash_32(logstart, FAT_HASH_BITS); >> diff --git a/fs/fat/inode.c b/fs/fat/inode.c >> index 491320b..c4c286a 100644 >> --- a/fs/fat/inode.c >> +++ b/fs/fat/inode.c >> @@ -384,7 +384,7 @@ static int fat_calc_dir_size(struct inode *inode) >> } >> >> /* doesn't deal with root inode */ >> -static int fat_fill_inode(struct inode *inode, struct msdos_dir_entry >> *de) >> +int fat_fill_inode(struct inode *inode, struct msdos_dir_entry *de) >> { >> struct msdos_sb_info *sbi = MSDOS_SB(inode->i_sb); >> int error; >> diff --git a/fs/fat/nfs.c b/fs/fat/nfs.c >> index 08ff9fa..e94da33 100644 >> --- a/fs/fat/nfs.c >> +++ b/fs/fat/nfs.c >> @@ -213,6 +213,53 @@ static struct dentry >> *fat_fh_to_parent_nostale(struct super_block *sb, >> } >> >> /* >> + * Rebuild the parent for a directory that is not connected >> + * to the filesystem root >> + */ >> +static >> +struct inode *fat_rebuild_parent(struct super_block *sb, int >> parent_logstart) >> +{ >> + int search_clus, clus_to_match; >> + struct msdos_dir_entry *de; >> + struct inode *parent = NULL; >> + struct inode *dummy_grand_parent = NULL; >> + struct fat_slot_info sinfo; >> + struct msdos_sb_info *sbi = MSDOS_SB(sb); >> + sector_t blknr = fat_clus_to_blknr(sbi, parent_logstart); >> + struct buffer_head *parent_bh = sb_bread(sb, blknr); >> + if (!parent_bh) { >> + fat_msg(sb, KERN_ERR, >> + "unable to read cluster of parent directory"); >> + return NULL; >> + } >> + >> + de = (struct msdos_dir_entry *) parent_bh->b_data; >> + clus_to_match = fat_get_start(sbi, &de[0]); >> + search_clus = fat_get_start(sbi, &de[1]); >> + >> + dummy_grand_parent = fat_dget(sb, search_clus); >> + if (!dummy_grand_parent) { >> + dummy_grand_parent = new_inode(sb); >> + if (!dummy_grand_parent) { >> + brelse(parent_bh); >> + return parent; >> + } >> + >> + dummy_grand_parent->i_ino = iunique(sb, MSDOS_ROOT_INO); >> + fat_fill_inode(dummy_grand_parent, &de[1]); >> + MSDOS_I(dummy_grand_parent)->i_pos = -1; >> + } >> + >> + if (!fat_scan_logstart(dummy_grand_parent, clus_to_match, &sinfo)) >> + parent = fat_build_inode(sb, sinfo.de, sinfo.i_pos); >> + >> + brelse(parent_bh); >> + iput(dummy_grand_parent); >> + >> + return parent; >> +} >> + >> +/* >> * Find the parent for a directory that is not currently connected to >> * the filesystem root. >> * >> @@ -224,10 +271,13 @@ static struct dentry *fat_get_parent(struct >> dentry *child_dir) >> struct buffer_head *bh = NULL; >> struct msdos_dir_entry *de; >> struct inode *parent_inode = NULL; >> + struct msdos_sb_info *sbi = MSDOS_SB(sb); >> >> if (!fat_get_dotdot_entry(child_dir->d_inode, &bh, &de)) { >> - int parent_logstart = fat_get_start(MSDOS_SB(sb), de); >> + int parent_logstart = fat_get_start(sbi, de); >> parent_inode = fat_dget(sb, parent_logstart); >> + if (!parent_inode && sbi->options.nfs == FAT_NFS_NOSTALE_RO) >> + parent_inode = fat_rebuild_parent(sb, parent_logstart); >> } >> brelse(bh); > > -- > OGAWA Hirofumi <hirofumi@xxxxxxxxxxxxxxxxxx> > -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html