vfat: shortname=always Maximum compatibility is achieved by only creating (potentially mangled) short filenames for vfat. A per-mount cache is kept, so common Linux operations like "stat" etc. on just-created files doesn't fail. Signed-off-by: Rusty Russell --- fs/fat/fat.h | 8 ++- fs/fat/inode.c | 21 ++++++- fs/fat/namei_msdos.c | 3 - fs/fat/namei_vfat.c | 135 ++++++++++++++++++++++++++++++++++++++++++++------- 4 files changed, 143 insertions(+), 24 deletions(-) diff --git a/fs/fat/fat.h b/fs/fat/fat.h --- a/fs/fat/fat.h +++ b/fs/fat/fat.h @@ -16,6 +16,7 @@ #define VFAT_SFN_DISPLAY_WINNT 0x0004 /* emulate winnt rule for display */ #define VFAT_SFN_CREATE_WIN95 0x0100 /* emulate win95 rule for create */ #define VFAT_SFN_CREATE_WINNT 0x0200 /* emulate winnt rule for create */ +#define VFAT_SFN_CREATE_SHORTALWAYS 0x0400 /* create shortname only */ #define FAT_ERRORS_CONT 1 /* ignore error and continue */ #define FAT_ERRORS_PANIC 2 /* panic on error */ @@ -83,6 +84,9 @@ struct msdos_sb_info { spinlock_t inode_hash_lock; struct hlist_head inode_hashtable[FAT_HASH_SIZE]; + + struct list_head short_long_map; + void (*put_super)(struct msdos_sb_info *); }; #define FAT_CACHE_VALID 0 /* special case for valid cache */ @@ -316,7 +320,9 @@ extern struct inode *fat_build_inode(str struct msdos_dir_entry *de, loff_t i_pos); extern int fat_sync_inode(struct inode *inode); extern int fat_fill_super(struct super_block *sb, void *data, int silent, - const struct inode_operations *fs_dir_inode_ops, int isvfat); + const struct inode_operations *fs_dir_inode_ops, + int isvfat, + void (*put_super)(struct msdos_sb_info *)); extern int fat_flush_inodes(struct super_block *sb, struct inode *i1, struct inode *i2); diff --git a/fs/fat/inode.c b/fs/fat/inode.c --- a/fs/fat/inode.c +++ b/fs/fat/inode.c @@ -485,6 +485,8 @@ static void fat_put_super(struct super_b } sb->s_fs_info = NULL; + if (sbi->put_super) + sbi->put_super(sbi); kfree(sbi); unlock_kernel(); @@ -872,10 +874,10 @@ enum { Opt_usefree, Opt_nocase, Opt_quiet, Opt_showexec, Opt_debug, Opt_immutable, Opt_dots, Opt_nodots, Opt_charset, Opt_shortname_lower, Opt_shortname_win95, - Opt_shortname_winnt, Opt_shortname_mixed, Opt_utf8_no, Opt_utf8_yes, - Opt_uni_xl_no, Opt_uni_xl_yes, Opt_nonumtail_no, Opt_nonumtail_yes, - Opt_obsolate, Opt_flush, Opt_tz_utc, Opt_rodir, Opt_err_cont, - Opt_err_panic, Opt_err_ro, Opt_err, + Opt_shortname_winnt, Opt_shortname_mixed, Opt_shortname_always, + Opt_utf8_no, Opt_utf8_yes, Opt_uni_xl_no, Opt_uni_xl_yes, + Opt_nonumtail_no, Opt_nonumtail_yes, Opt_obsolate, Opt_flush, + Opt_tz_utc, Opt_rodir, Opt_err_cont, Opt_err_panic, Opt_err_ro, Opt_err, }; static const match_table_t fat_tokens = { @@ -929,6 +931,7 @@ static const match_table_t vfat_tokens = {Opt_shortname_win95, "shortname=win95"}, {Opt_shortname_winnt, "shortname=winnt"}, {Opt_shortname_mixed, "shortname=mixed"}, + {Opt_shortname_always, "shortname=always"}, {Opt_utf8_no, "utf8=0"}, /* 0 or no or false */ {Opt_utf8_no, "utf8=no"}, {Opt_utf8_no, "utf8=false"}, @@ -1119,6 +1122,11 @@ static int parse_options(char *options, opts->shortname = VFAT_SFN_DISPLAY_WINNT | VFAT_SFN_CREATE_WIN95; break; + case Opt_shortname_always: + opts->shortname = VFAT_SFN_DISPLAY_WINNT + | VFAT_SFN_CREATE_WINNT + | VFAT_SFN_CREATE_SHORTALWAYS; + break; case Opt_utf8_no: /* 0 or no or false */ opts->utf8 = 0; break; @@ -1214,7 +1222,8 @@ static int fat_read_root(struct inode *i * Read the super block of an MS-DOS FS. */ int fat_fill_super(struct super_block *sb, void *data, int silent, - const struct inode_operations *fs_dir_inode_ops, int isvfat) + const struct inode_operations *fs_dir_inode_ops, int isvfat, + void (*put_super)(struct msdos_sb_info *)) { struct inode *root_inode = NULL, *fat_inode = NULL; struct buffer_head *bh; @@ -1243,6 +1252,8 @@ int fat_fill_super(struct super_block *s sb->s_op = &fat_sops; sb->s_export_op = &fat_export_ops; sbi->dir_ops = fs_dir_inode_ops; + sbi->put_super = put_super; + INIT_LIST_HEAD(&sbi->short_long_map); error = parse_options(data, isvfat, silent, &debug, &sbi->options); if (error) diff --git a/fs/fat/namei_msdos.c b/fs/fat/namei_msdos.c --- a/fs/fat/namei_msdos.c +++ b/fs/fat/namei_msdos.c @@ -662,7 +662,8 @@ static int msdos_fill_super(struct super { int res; - res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0); + res = fat_fill_super(sb, data, silent, &msdos_dir_inode_operations, 0, + NULL); if (res) return res; diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c --- a/fs/fat/namei_vfat.c +++ b/fs/fat/namei_vfat.c @@ -85,15 +85,19 @@ static int vfat_revalidate_ci(struct den } /* returns the length of a struct qstr, ignoring trailing dots */ -static unsigned int vfat_striptail_len(struct qstr *qstr) +static unsigned int vfat_striptail_len(const unsigned char *name, + unsigned int len) { - unsigned int len = qstr->len; - - while (len && qstr->name[len - 1] == '.') + while (len && name[len - 1] == '.') len--; return len; } +static unsigned int vfat_striptail_qstr(struct qstr *qstr) +{ + return vfat_striptail_len(qstr->name, qstr->len); +} + /* * Compute the hash for the vfat name corresponding to the dentry. * Note: if the name is invalid, we leave the hash code unchanged so @@ -102,7 +106,7 @@ static unsigned int vfat_striptail_len(s */ static int vfat_hash(struct dentry *dentry, struct qstr *qstr) { - qstr->hash = full_name_hash(qstr->name, vfat_striptail_len(qstr)); + qstr->hash = full_name_hash(qstr->name, vfat_striptail_qstr(qstr)); return 0; } @@ -120,7 +124,7 @@ static int vfat_hashi(struct dentry *den unsigned long hash; name = qstr->name; - len = vfat_striptail_len(qstr); + len = vfat_striptail_qstr(qstr); hash = init_name_hash(); while (len--) @@ -139,8 +143,8 @@ static int vfat_cmpi(struct dentry *dent unsigned int alen, blen; /* A filename cannot end in '.' or we treat it like it has none */ - alen = vfat_striptail_len(a); - blen = vfat_striptail_len(b); + alen = vfat_striptail_qstr(a); + blen = vfat_striptail_qstr(b); if (alen == blen) { if (nls_strnicmp(t, a->name, b->name, alen) == 0) return 0; @@ -156,8 +160,8 @@ static int vfat_cmp(struct dentry *dentr unsigned int alen, blen; /* A filename cannot end in '.' or we treat it like it has none */ - alen = vfat_striptail_len(a); - blen = vfat_striptail_len(b); + alen = vfat_striptail_qstr(a); + blen = vfat_striptail_qstr(b); if (alen == blen) { if (strncmp(a->name, b->name, alen) == 0) return 0; @@ -585,6 +589,70 @@ xlate_to_uni(const unsigned char *name, return 0; } +struct vfat_slmap { + struct list_head list; + unsigned char msdos_name[MSDOS_NAME]; + unsigned int len; + unsigned char name[0]; +}; + +/* sb must already be locked for all of these: */ +static int vfat_slmap_add(struct msdos_sb_info *sbi, + const unsigned char *name, unsigned int len, + const unsigned char msdos_name[MSDOS_NAME]) +{ + struct vfat_slmap *sl; + + sl = kmalloc(sizeof(*sl) + len, GFP_KERNEL); + if (!sl) + return -ENOMEM; + + memcpy(sl->msdos_name, msdos_name, sizeof(sl->msdos_name)); + memcpy(sl->name, name, len); + sl->len = vfat_striptail_len(name, len); + list_add(&sl->list, &sbi->short_long_map); +} + +static struct vfat_slmap *vfat_slmap_find(struct msdos_sb_info *sbi, + const unsigned char *name, + unsigned int len) +{ + struct vfat_slmap *sl; + + len = vfat_striptail_len(name, len); + list_for_each_entry(sl, &sbi->short_long_map, list) { + if (sl->len != len) + continue; + if (memcmp(sl->name, name, len) != 0) + continue; + return sl; + } + return NULL; +} + +static void vfat_slmap_del(struct msdos_sb_info *sbi, + const unsigned char *name, unsigned int len) +{ + struct vfat_slmap *sl; + + sl = vfat_slmap_find(sbi, name, len); + if (sl) { + list_del(&sl->list); + kfree(sl); + } +} + +/* We simply throw away cache of long names here. */ +static void vfat_put_super(struct msdos_sb_info *sbi) +{ + struct vfat_slmap *sl, *next; + + list_for_each_entry_safe(sl, next, &sbi->short_long_map, list) { + list_del(&sl->list); + kfree(sl); + } +} + static int vfat_build_slots(struct inode *dir, const unsigned char *name, int len, int is_dir, int cluster, struct timespec *ts, @@ -627,6 +695,14 @@ static int vfat_build_slots(struct inode goto shortname; } + if (opts->shortname & VFAT_SFN_CREATE_SHORTALWAYS) { + de = (struct msdos_dir_entry *)slots; + err = vfat_slmap_add(sbi, name, len, msdos_name); + if (err) + goto out_free; + goto shortname; + } + /* build the entry of long file name */ cksum = fat_checksum(msdos_name); @@ -671,7 +747,7 @@ static int vfat_add_entry(struct inode * unsigned int len; int err, nr_slots; - len = vfat_striptail_len(qname); + len = vfat_striptail_qstr(qname); if (len == 0) return -ENOENT; @@ -695,17 +771,38 @@ static int vfat_add_entry(struct inode * else mark_inode_dirty(dir); cleanup: + if (err) + vfat_slmap_del(MSDOS_SB(dir->i_sb), qname->name, qname->len); kfree(slots); return err; } +static int vfat_remove_entries(struct inode *dir, + struct qstr *qname, + struct fat_slot_info *sinfo) +{ + int err = fat_remove_entries(dir, sinfo); + if (!err) + vfat_slmap_del(MSDOS_SB(dir->i_sb), qname->name, qname->len); + return err; +} + static int vfat_find(struct inode *dir, struct qstr *qname, struct fat_slot_info *sinfo) { - unsigned int len = vfat_striptail_len(qname); + int err; + unsigned int len = vfat_striptail_qstr(qname); if (len == 0) return -ENOENT; - return fat_search_long(dir, qname->name, len, sinfo); + err = fat_search_long(dir, qname->name, len, sinfo); + if (err == -ENOENT) { + struct vfat_slmap *sl; + sl = vfat_slmap_find(MSDOS_SB(dir->i_sb), + qname->name, qname->len); + if (sl) + err = fat_scan(dir, sl->msdos_name, sinfo); + } + return err; } static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, @@ -817,7 +914,8 @@ static int vfat_rmdir(struct inode *dir, if (err) goto out; - err = fat_remove_entries(dir, &sinfo); /* and releases bh */ + /* and releases bh */ + err = vfat_remove_entries(dir, &dentry->d_name, &sinfo); if (err) goto out; drop_nlink(dir); @@ -844,7 +942,8 @@ static int vfat_unlink(struct inode *dir if (err) goto out; - err = fat_remove_entries(dir, &sinfo); /* and releases bh */ + /* and releases bh */ + err = vfat_remove_entries(dir, &dentry->d_name, &sinfo); if (err) goto out; clear_nlink(inode); @@ -975,7 +1074,8 @@ static int vfat_rename(struct inode *old inc_nlink(new_dir); } - err = fat_remove_entries(old_dir, &old_sinfo); /* and releases bh */ + /* and releases bh */ + err = vfat_remove_entries(old_dir, &old_dentry->d_name, &old_sinfo); old_sinfo.bh = NULL; if (err) goto error_dotdot; @@ -1051,7 +1151,8 @@ static int vfat_fill_super(struct super_ { int res; - res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1); + res = fat_fill_super(sb, data, silent, &vfat_dir_inode_operations, 1, + vfat_put_super); if (res) return res;