diff options
| -rw-r--r-- | fs/fat/namei_vfat.c | 124 |
1 files changed, 80 insertions, 44 deletions
diff --git a/fs/fat/namei_vfat.c b/fs/fat/namei_vfat.c index 419deabfb9b..d585398f9f6 100644 --- a/fs/fat/namei_vfat.c +++ b/fs/fat/namei_vfat.c @@ -24,27 +24,67 @@ #include <linux/namei.h> #include "fat.h" -static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd) +/* + * If new entry was created in the parent, it could create the 8.3 + * alias (the shortname of logname). So, the parent may have the + * negative-dentry which matches the created 8.3 alias. + * + * If it happened, the negative dentry isn't actually negative + * anymore. So, drop it. + */ +static int vfat_revalidate_shortname(struct dentry *dentry) { int ret = 1; - - if (!dentry->d_inode && - nd && !(nd->flags & LOOKUP_CONTINUE) && (nd->flags & LOOKUP_CREATE)) - /* - * negative dentry is dropped, in order to make sure - * to use the name which a user desires if this is - * create path. - */ + spin_lock(&dentry->d_lock); + if (dentry->d_time != dentry->d_parent->d_inode->i_version) ret = 0; - else { - spin_lock(&dentry->d_lock); - if (dentry->d_time != dentry->d_parent->d_inode->i_version) - ret = 0; - spin_unlock(&dentry->d_lock); - } + spin_unlock(&dentry->d_lock); return ret; } +static int vfat_revalidate(struct dentry *dentry, struct nameidata *nd) +{ + /* This is not negative dentry. Always valid. */ + if (dentry->d_inode) + return 1; + return vfat_revalidate_shortname(dentry); +} + +static int vfat_revalidate_ci(struct dentry *dentry, struct nameidata *nd) +{ + /* + * This is not negative dentry. Always valid. + * + * Note, rename() to existing directory entry will have ->d_inode, + * and will use existing name which isn't specified name by user. + * + * We may be able to drop this positive dentry here. But dropping + * positive dentry isn't good idea. So it's unsupported like + * rename("filename", "FILENAME") for now. + */ + if (dentry->d_inode) + return 1; + + /* + * This may be nfsd (or something), anyway, we can't see the + * intent of this. So, since this can be for creation, drop it. + */ + if (!nd) + return 0; + + /* + * Drop the negative dentry, in order to make sure to use the + * case sensitive name which is specified by user if this is + * for creation. + */ + if (!(nd->flags & (LOOKUP_CONTINUE | LOOKUP_PARENT))) { + if (nd->flags & LOOKUP_CREATE) + return 0; + } + + return vfat_revalidate_shortname(dentry); +} + /* returns the length of a struct qstr, ignoring trailing dots */ static unsigned int vfat_striptail_len(struct qstr *qstr) { @@ -126,25 +166,16 @@ static int vfat_cmp(struct dentry *dentry, struct qstr *a, struct qstr *b) return 1; } -static struct dentry_operations vfat_dentry_ops[4] = { - { - .d_hash = vfat_hashi, - .d_compare = vfat_cmpi, - }, - { - .d_revalidate = vfat_revalidate, - .d_hash = vfat_hashi, - .d_compare = vfat_cmpi, - }, - { - .d_hash = vfat_hash, - .d_compare = vfat_cmp, - }, - { - .d_revalidate = vfat_revalidate, - .d_hash = vfat_hash, - .d_compare = vfat_cmp, - } +static struct dentry_operations vfat_ci_dentry_ops = { + .d_revalidate = vfat_revalidate_ci, + .d_hash = vfat_hashi, + .d_compare = vfat_cmpi, +}; + +static struct dentry_operations vfat_dentry_ops = { + .d_revalidate = vfat_revalidate, + .d_hash = vfat_hash, + .d_compare = vfat_cmp, }; /* Characters that are undesirable in an MS-DOS file name */ @@ -685,29 +716,35 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, struct fat_slot_info sinfo; struct inode *inode; struct dentry *alias; - int err, table; + int err; lock_super(sb); - table = (MSDOS_SB(sb)->options.name_check == 's') ? 2 : 0; - dentry->d_op = &vfat_dentry_ops[table]; err = vfat_find(dir, &dentry->d_name, &sinfo); if (err) { if (err == -ENOENT) { - table++; inode = NULL; goto out; } goto error; } + inode = fat_build_inode(sb, sinfo.de, sinfo.i_pos); brelse(sinfo.bh); if (IS_ERR(inode)) { err = PTR_ERR(inode); goto error; } + alias = d_find_alias(inode); - if (alias) { + if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) { + /* + * This inode has non DCACHE_DISCONNECTED dentry. This + * means, the user did ->lookup() by an another name + * (longname vs 8.3 alias of it) in past. + * + * Switch to new one for reason of locality if possible. + */ if (d_invalidate(alias) == 0) dput(alias); else { @@ -715,15 +752,14 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, unlock_super(sb); return alias; } - } out: unlock_super(sb); - dentry->d_op = &vfat_dentry_ops[table]; + dentry->d_op = sb->s_root->d_op; dentry->d_time = dentry->d_parent->d_inode->i_version; dentry = d_splice_alias(inode, dentry); if (dentry) { - dentry->d_op = &vfat_dentry_ops[table]; + dentry->d_op = sb->s_root->d_op; dentry->d_time = dentry->d_parent->d_inode->i_version; } return dentry; @@ -1022,9 +1058,9 @@ static int vfat_fill_super(struct super_block *sb, void *data, int silent) return res; if (MSDOS_SB(sb)->options.name_check != 's') - sb->s_root->d_op = &vfat_dentry_ops[0]; + sb->s_root->d_op = &vfat_ci_dentry_ops; else - sb->s_root->d_op = &vfat_dentry_ops[2]; + sb->s_root->d_op = &vfat_dentry_ops; return 0; } |