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-rw-r--r--fs/Kconfig1
-rw-r--r--fs/Makefile1
-rw-r--r--fs/btrfs/ioctl.c20
-rw-r--r--fs/dcache.c2
-rw-r--r--fs/ecryptfs/main.c7
-rw-r--r--fs/ext4/namei.c95
-rw-r--r--fs/internal.h7
-rw-r--r--fs/namei.c41
-rw-r--r--fs/namespace.c27
-rw-r--r--fs/nfsd/nfs4proc.c7
-rw-r--r--fs/open.c23
-rw-r--r--fs/overlayfs/Kconfig10
-rw-r--r--fs/overlayfs/Makefile7
-rw-r--r--fs/overlayfs/copy_up.c414
-rw-r--r--fs/overlayfs/dir.c921
-rw-r--r--fs/overlayfs/inode.c425
-rw-r--r--fs/overlayfs/overlayfs.h191
-rw-r--r--fs/overlayfs/readdir.c590
-rw-r--r--fs/overlayfs/super.c796
-rw-r--r--fs/splice.c1
20 files changed, 3527 insertions, 59 deletions
diff --git a/fs/Kconfig b/fs/Kconfig
index db5dc1598716..664991afe0c0 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -67,6 +67,7 @@ source "fs/quota/Kconfig"
67 67
68source "fs/autofs4/Kconfig" 68source "fs/autofs4/Kconfig"
69source "fs/fuse/Kconfig" 69source "fs/fuse/Kconfig"
70source "fs/overlayfs/Kconfig"
70 71
71menu "Caches" 72menu "Caches"
72 73
diff --git a/fs/Makefile b/fs/Makefile
index 90c88529892b..34a1b9dea6dd 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -104,6 +104,7 @@ obj-$(CONFIG_QNX6FS_FS) += qnx6/
104obj-$(CONFIG_AUTOFS4_FS) += autofs4/ 104obj-$(CONFIG_AUTOFS4_FS) += autofs4/
105obj-$(CONFIG_ADFS_FS) += adfs/ 105obj-$(CONFIG_ADFS_FS) += adfs/
106obj-$(CONFIG_FUSE_FS) += fuse/ 106obj-$(CONFIG_FUSE_FS) += fuse/
107obj-$(CONFIG_OVERLAYFS_FS) += overlayfs/
107obj-$(CONFIG_UDF_FS) += udf/ 108obj-$(CONFIG_UDF_FS) += udf/
108obj-$(CONFIG_SUN_OPENPROMFS) += openpromfs/ 109obj-$(CONFIG_SUN_OPENPROMFS) += openpromfs/
109obj-$(CONFIG_OMFS_FS) += omfs/ 110obj-$(CONFIG_OMFS_FS) += omfs/
diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c
index 8d2b76e29d3b..4399f0c3a4ce 100644
--- a/fs/btrfs/ioctl.c
+++ b/fs/btrfs/ioctl.c
@@ -765,23 +765,6 @@ out:
765 return ret; 765 return ret;
766} 766}
767 767
768/* copy of check_sticky in fs/namei.c()
769* It's inline, so penalty for filesystems that don't use sticky bit is
770* minimal.
771*/
772static inline int btrfs_check_sticky(struct inode *dir, struct inode *inode)
773{
774 kuid_t fsuid = current_fsuid();
775
776 if (!(dir->i_mode & S_ISVTX))
777 return 0;
778 if (uid_eq(inode->i_uid, fsuid))
779 return 0;
780 if (uid_eq(dir->i_uid, fsuid))
781 return 0;
782 return !capable(CAP_FOWNER);
783}
784
785/* copy of may_delete in fs/namei.c() 768/* copy of may_delete in fs/namei.c()
786 * Check whether we can remove a link victim from directory dir, check 769 * Check whether we can remove a link victim from directory dir, check
787 * whether the type of victim is right. 770 * whether the type of victim is right.
@@ -817,8 +800,7 @@ static int btrfs_may_delete(struct inode *dir, struct dentry *victim, int isdir)
817 return error; 800 return error;
818 if (IS_APPEND(dir)) 801 if (IS_APPEND(dir))
819 return -EPERM; 802 return -EPERM;
820 if (btrfs_check_sticky(dir, victim->d_inode)|| 803 if (check_sticky(dir, victim->d_inode) || IS_APPEND(victim->d_inode) ||
821 IS_APPEND(victim->d_inode)||
822 IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode)) 804 IS_IMMUTABLE(victim->d_inode) || IS_SWAPFILE(victim->d_inode))
823 return -EPERM; 805 return -EPERM;
824 if (isdir) { 806 if (isdir) {
diff --git a/fs/dcache.c b/fs/dcache.c
index d5a23fd0da90..3ffef7f4e5cd 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -2673,11 +2673,13 @@ struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry)
2673 if (!IS_ROOT(new)) { 2673 if (!IS_ROOT(new)) {
2674 spin_unlock(&inode->i_lock); 2674 spin_unlock(&inode->i_lock);
2675 dput(new); 2675 dput(new);
2676 iput(inode);
2676 return ERR_PTR(-EIO); 2677 return ERR_PTR(-EIO);
2677 } 2678 }
2678 if (d_ancestor(new, dentry)) { 2679 if (d_ancestor(new, dentry)) {
2679 spin_unlock(&inode->i_lock); 2680 spin_unlock(&inode->i_lock);
2680 dput(new); 2681 dput(new);
2682 iput(inode);
2681 return ERR_PTR(-EIO); 2683 return ERR_PTR(-EIO);
2682 } 2684 }
2683 write_seqlock(&rename_lock); 2685 write_seqlock(&rename_lock);
diff --git a/fs/ecryptfs/main.c b/fs/ecryptfs/main.c
index 1b119d3bf924..c4cd1fd86cc2 100644
--- a/fs/ecryptfs/main.c
+++ b/fs/ecryptfs/main.c
@@ -566,6 +566,13 @@ static struct dentry *ecryptfs_mount(struct file_system_type *fs_type, int flags
566 s->s_maxbytes = path.dentry->d_sb->s_maxbytes; 566 s->s_maxbytes = path.dentry->d_sb->s_maxbytes;
567 s->s_blocksize = path.dentry->d_sb->s_blocksize; 567 s->s_blocksize = path.dentry->d_sb->s_blocksize;
568 s->s_magic = ECRYPTFS_SUPER_MAGIC; 568 s->s_magic = ECRYPTFS_SUPER_MAGIC;
569 s->s_stack_depth = path.dentry->d_sb->s_stack_depth + 1;
570
571 rc = -EINVAL;
572 if (s->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
573 pr_err("eCryptfs: maximum fs stacking depth exceeded\n");
574 goto out_free;
575 }
569 576
570 inode = ecryptfs_get_inode(path.dentry->d_inode, s); 577 inode = ecryptfs_get_inode(path.dentry->d_inode, s);
571 rc = PTR_ERR(inode); 578 rc = PTR_ERR(inode);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index adb559de23c1..123798c5ac31 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -3148,6 +3148,39 @@ static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3148 } 3148 }
3149} 3149}
3150 3150
3151static struct inode *ext4_whiteout_for_rename(struct ext4_renament *ent,
3152 int credits, handle_t **h)
3153{
3154 struct inode *wh;
3155 handle_t *handle;
3156 int retries = 0;
3157
3158 /*
3159 * for inode block, sb block, group summaries,
3160 * and inode bitmap
3161 */
3162 credits += (EXT4_MAXQUOTAS_TRANS_BLOCKS(ent->dir->i_sb) +
3163 EXT4_XATTR_TRANS_BLOCKS + 4);
3164retry:
3165 wh = ext4_new_inode_start_handle(ent->dir, S_IFCHR | WHITEOUT_MODE,
3166 &ent->dentry->d_name, 0, NULL,
3167 EXT4_HT_DIR, credits);
3168
3169 handle = ext4_journal_current_handle();
3170 if (IS_ERR(wh)) {
3171 if (handle)
3172 ext4_journal_stop(handle);
3173 if (PTR_ERR(wh) == -ENOSPC &&
3174 ext4_should_retry_alloc(ent->dir->i_sb, &retries))
3175 goto retry;
3176 } else {
3177 *h = handle;
3178 init_special_inode(wh, wh->i_mode, WHITEOUT_DEV);
3179 wh->i_op = &ext4_special_inode_operations;
3180 }
3181 return wh;
3182}
3183
3151/* 3184/*
3152 * Anybody can rename anything with this: the permission checks are left to the 3185 * Anybody can rename anything with this: the permission checks are left to the
3153 * higher-level routines. 3186 * higher-level routines.
@@ -3157,7 +3190,8 @@ static void ext4_update_dir_count(handle_t *handle, struct ext4_renament *ent)
3157 * This comes from rename(const char *oldpath, const char *newpath) 3190 * This comes from rename(const char *oldpath, const char *newpath)
3158 */ 3191 */
3159static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry, 3192static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3160 struct inode *new_dir, struct dentry *new_dentry) 3193 struct inode *new_dir, struct dentry *new_dentry,
3194 unsigned int flags)
3161{ 3195{
3162 handle_t *handle = NULL; 3196 handle_t *handle = NULL;
3163 struct ext4_renament old = { 3197 struct ext4_renament old = {
@@ -3172,6 +3206,9 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3172 }; 3206 };
3173 int force_reread; 3207 int force_reread;
3174 int retval; 3208 int retval;
3209 struct inode *whiteout = NULL;
3210 int credits;
3211 u8 old_file_type;
3175 3212
3176 dquot_initialize(old.dir); 3213 dquot_initialize(old.dir);
3177 dquot_initialize(new.dir); 3214 dquot_initialize(new.dir);
@@ -3210,11 +3247,17 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3210 if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC)) 3247 if (new.inode && !test_opt(new.dir->i_sb, NO_AUTO_DA_ALLOC))
3211 ext4_alloc_da_blocks(old.inode); 3248 ext4_alloc_da_blocks(old.inode);
3212 3249
3213 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, 3250 credits = (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) +
3214 (2 * EXT4_DATA_TRANS_BLOCKS(old.dir->i_sb) + 3251 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2);
3215 EXT4_INDEX_EXTRA_TRANS_BLOCKS + 2)); 3252 if (!(flags & RENAME_WHITEOUT)) {
3216 if (IS_ERR(handle)) 3253 handle = ext4_journal_start(old.dir, EXT4_HT_DIR, credits);
3217 return PTR_ERR(handle); 3254 if (IS_ERR(handle))
3255 return PTR_ERR(handle);
3256 } else {
3257 whiteout = ext4_whiteout_for_rename(&old, credits, &handle);
3258 if (IS_ERR(whiteout))
3259 return PTR_ERR(whiteout);
3260 }
3218 3261
3219 if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir)) 3262 if (IS_DIRSYNC(old.dir) || IS_DIRSYNC(new.dir))
3220 ext4_handle_sync(handle); 3263 ext4_handle_sync(handle);
@@ -3242,13 +3285,26 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3242 */ 3285 */
3243 force_reread = (new.dir->i_ino == old.dir->i_ino && 3286 force_reread = (new.dir->i_ino == old.dir->i_ino &&
3244 ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA)); 3287 ext4_test_inode_flag(new.dir, EXT4_INODE_INLINE_DATA));
3288
3289 old_file_type = old.de->file_type;
3290 if (whiteout) {
3291 /*
3292 * Do this before adding a new entry, so the old entry is sure
3293 * to be still pointing to the valid old entry.
3294 */
3295 retval = ext4_setent(handle, &old, whiteout->i_ino,
3296 EXT4_FT_CHRDEV);
3297 if (retval)
3298 goto end_rename;
3299 ext4_mark_inode_dirty(handle, whiteout);
3300 }
3245 if (!new.bh) { 3301 if (!new.bh) {
3246 retval = ext4_add_entry(handle, new.dentry, old.inode); 3302 retval = ext4_add_entry(handle, new.dentry, old.inode);
3247 if (retval) 3303 if (retval)
3248 goto end_rename; 3304 goto end_rename;
3249 } else { 3305 } else {
3250 retval = ext4_setent(handle, &new, 3306 retval = ext4_setent(handle, &new,
3251 old.inode->i_ino, old.de->file_type); 3307 old.inode->i_ino, old_file_type);
3252 if (retval) 3308 if (retval)
3253 goto end_rename; 3309 goto end_rename;
3254 } 3310 }
@@ -3263,10 +3319,12 @@ static int ext4_rename(struct inode *old_dir, struct dentry *old_dentry,
3263 old.inode->i_ctime = ext4_current_time(old.inode); 3319 old.inode->i_ctime = ext4_current_time(old.inode);
3264 ext4_mark_inode_dirty(handle, old.inode); 3320 ext4_mark_inode_dirty(handle, old.inode);
3265 3321
3266 /* 3322 if (!whiteout) {
3267 * ok, that's it 3323 /*
3268 */ 3324 * ok, that's it
3269 ext4_rename_delete(handle, &old, force_reread); 3325 */
3326 ext4_rename_delete(handle, &old, force_reread);
3327 }
3270 3328
3271 if (new.inode) { 3329 if (new.inode) {
3272 ext4_dec_count(handle, new.inode); 3330 ext4_dec_count(handle, new.inode);
@@ -3302,6 +3360,12 @@ end_rename:
3302 brelse(old.dir_bh); 3360 brelse(old.dir_bh);
3303 brelse(old.bh); 3361 brelse(old.bh);
3304 brelse(new.bh); 3362 brelse(new.bh);
3363 if (whiteout) {
3364 if (retval)
3365 drop_nlink(whiteout);
3366 unlock_new_inode(whiteout);
3367 iput(whiteout);
3368 }
3305 if (handle) 3369 if (handle)
3306 ext4_journal_stop(handle); 3370 ext4_journal_stop(handle);
3307 return retval; 3371 return retval;
@@ -3434,18 +3498,15 @@ static int ext4_rename2(struct inode *old_dir, struct dentry *old_dentry,
3434 struct inode *new_dir, struct dentry *new_dentry, 3498 struct inode *new_dir, struct dentry *new_dentry,
3435 unsigned int flags) 3499 unsigned int flags)
3436{ 3500{
3437 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) 3501 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
3438 return -EINVAL; 3502 return -EINVAL;
3439 3503
3440 if (flags & RENAME_EXCHANGE) { 3504 if (flags & RENAME_EXCHANGE) {
3441 return ext4_cross_rename(old_dir, old_dentry, 3505 return ext4_cross_rename(old_dir, old_dentry,
3442 new_dir, new_dentry); 3506 new_dir, new_dentry);
3443 } 3507 }
3444 /* 3508
3445 * Existence checking was done by the VFS, otherwise "RENAME_NOREPLACE" 3509 return ext4_rename(old_dir, old_dentry, new_dir, new_dentry, flags);
3446 * is equivalent to regular rename.
3447 */
3448 return ext4_rename(old_dir, old_dentry, new_dir, new_dentry);
3449} 3510}
3450 3511
3451/* 3512/*
diff --git a/fs/internal.h b/fs/internal.h
index 9477f8f6aefc..757ba2abf21e 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -47,7 +47,6 @@ extern void __init chrdev_init(void);
47/* 47/*
48 * namei.c 48 * namei.c
49 */ 49 */
50extern int __inode_permission(struct inode *, int);
51extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *); 50extern int user_path_mountpoint_at(int, const char __user *, unsigned int, struct path *);
52extern int vfs_path_lookup(struct dentry *, struct vfsmount *, 51extern int vfs_path_lookup(struct dentry *, struct vfsmount *,
53 const char *, unsigned int, struct path *); 52 const char *, unsigned int, struct path *);
@@ -139,12 +138,6 @@ extern long prune_dcache_sb(struct super_block *sb, unsigned long nr_to_scan,
139extern int rw_verify_area(int, struct file *, const loff_t *, size_t); 138extern int rw_verify_area(int, struct file *, const loff_t *, size_t);
140 139
141/* 140/*
142 * splice.c
143 */
144extern long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
145 loff_t *opos, size_t len, unsigned int flags);
146
147/*
148 * pipe.c 141 * pipe.c
149 */ 142 */
150extern const struct file_operations pipefifo_fops; 143extern const struct file_operations pipefifo_fops;
diff --git a/fs/namei.c b/fs/namei.c
index 43927d14db67..42df664e95e5 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -416,6 +416,7 @@ int __inode_permission(struct inode *inode, int mask)
416 416
417 return security_inode_permission(inode, mask); 417 return security_inode_permission(inode, mask);
418} 418}
419EXPORT_SYMBOL(__inode_permission);
419 420
420/** 421/**
421 * sb_permission - Check superblock-level permissions 422 * sb_permission - Check superblock-level permissions
@@ -2383,22 +2384,17 @@ kern_path_mountpoint(int dfd, const char *name, struct path *path,
2383} 2384}
2384EXPORT_SYMBOL(kern_path_mountpoint); 2385EXPORT_SYMBOL(kern_path_mountpoint);
2385 2386
2386/* 2387int __check_sticky(struct inode *dir, struct inode *inode)
2387 * It's inline, so penalty for filesystems that don't use sticky bit is
2388 * minimal.
2389 */
2390static inline int check_sticky(struct inode *dir, struct inode *inode)
2391{ 2388{
2392 kuid_t fsuid = current_fsuid(); 2389 kuid_t fsuid = current_fsuid();
2393 2390
2394 if (!(dir->i_mode & S_ISVTX))
2395 return 0;
2396 if (uid_eq(inode->i_uid, fsuid)) 2391 if (uid_eq(inode->i_uid, fsuid))
2397 return 0; 2392 return 0;
2398 if (uid_eq(dir->i_uid, fsuid)) 2393 if (uid_eq(dir->i_uid, fsuid))
2399 return 0; 2394 return 0;
2400 return !capable_wrt_inode_uidgid(inode, CAP_FOWNER); 2395 return !capable_wrt_inode_uidgid(inode, CAP_FOWNER);
2401} 2396}
2397EXPORT_SYMBOL(__check_sticky);
2402 2398
2403/* 2399/*
2404 * Check whether we can remove a link victim from directory dir, check 2400 * Check whether we can remove a link victim from directory dir, check
@@ -3064,9 +3060,12 @@ finish_open_created:
3064 error = may_open(&nd->path, acc_mode, open_flag); 3060 error = may_open(&nd->path, acc_mode, open_flag);
3065 if (error) 3061 if (error)
3066 goto out; 3062 goto out;
3067 file->f_path.mnt = nd->path.mnt; 3063
3068 error = finish_open(file, nd->path.dentry, NULL, opened); 3064 BUG_ON(*opened & FILE_OPENED); /* once it's opened, it's opened */
3069 if (error) { 3065 error = vfs_open(&nd->path, file, current_cred());
3066 if (!error) {
3067 *opened |= FILE_OPENED;
3068 } else {
3070 if (error == -EOPENSTALE) 3069 if (error == -EOPENSTALE)
3071 goto stale_open; 3070 goto stale_open;
3072 goto out; 3071 goto out;
@@ -4210,12 +4209,16 @@ SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
4210 bool should_retry = false; 4209 bool should_retry = false;
4211 int error; 4210 int error;
4212 4211
4213 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE)) 4212 if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE | RENAME_WHITEOUT))
4214 return -EINVAL; 4213 return -EINVAL;
4215 4214
4216 if ((flags & RENAME_NOREPLACE) && (flags & RENAME_EXCHANGE)) 4215 if ((flags & (RENAME_NOREPLACE | RENAME_WHITEOUT)) &&
4216 (flags & RENAME_EXCHANGE))
4217 return -EINVAL; 4217 return -EINVAL;
4218 4218
4219 if ((flags & RENAME_WHITEOUT) && !capable(CAP_MKNOD))
4220 return -EPERM;
4221
4219retry: 4222retry:
4220 from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags); 4223 from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
4221 if (IS_ERR(from)) { 4224 if (IS_ERR(from)) {
@@ -4347,6 +4350,20 @@ SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newna
4347 return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0); 4350 return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
4348} 4351}
4349 4352
4353int vfs_whiteout(struct inode *dir, struct dentry *dentry)
4354{
4355 int error = may_create(dir, dentry);
4356 if (error)
4357 return error;
4358
4359 if (!dir->i_op->mknod)
4360 return -EPERM;
4361
4362 return dir->i_op->mknod(dir, dentry,
4363 S_IFCHR | WHITEOUT_MODE, WHITEOUT_DEV);
4364}
4365EXPORT_SYMBOL(vfs_whiteout);
4366
4350int readlink_copy(char __user *buffer, int buflen, const char *link) 4367int readlink_copy(char __user *buffer, int buflen, const char *link)
4351{ 4368{
4352 int len = PTR_ERR(link); 4369 int len = PTR_ERR(link);
diff --git a/fs/namespace.c b/fs/namespace.c
index fbba8b17330d..5b66b2b3624d 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1686,6 +1686,33 @@ void drop_collected_mounts(struct vfsmount *mnt)
1686 namespace_unlock(); 1686 namespace_unlock();
1687} 1687}
1688 1688
1689/**
1690 * clone_private_mount - create a private clone of a path
1691 *
1692 * This creates a new vfsmount, which will be the clone of @path. The new will
1693 * not be attached anywhere in the namespace and will be private (i.e. changes
1694 * to the originating mount won't be propagated into this).
1695 *
1696 * Release with mntput().
1697 */
1698struct vfsmount *clone_private_mount(struct path *path)
1699{
1700 struct mount *old_mnt = real_mount(path->mnt);
1701 struct mount *new_mnt;
1702
1703 if (IS_MNT_UNBINDABLE(old_mnt))
1704 return ERR_PTR(-EINVAL);
1705
1706 down_read(&namespace_sem);
1707 new_mnt = clone_mnt(old_mnt, path->dentry, CL_PRIVATE);
1708 up_read(&namespace_sem);
1709 if (IS_ERR(new_mnt))
1710 return ERR_CAST(new_mnt);
1711
1712 return &new_mnt->mnt;
1713}
1714EXPORT_SYMBOL_GPL(clone_private_mount);
1715
1689int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg, 1716int iterate_mounts(int (*f)(struct vfsmount *, void *), void *arg,
1690 struct vfsmount *root) 1717 struct vfsmount *root)
1691{ 1718{
diff --git a/fs/nfsd/nfs4proc.c b/fs/nfsd/nfs4proc.c
index cdeb3cfd6f32..0beb023f25ac 100644
--- a/fs/nfsd/nfs4proc.c
+++ b/fs/nfsd/nfs4proc.c
@@ -1272,7 +1272,8 @@ static bool need_wrongsec_check(struct svc_rqst *rqstp)
1272 */ 1272 */
1273 if (argp->opcnt == resp->opcnt) 1273 if (argp->opcnt == resp->opcnt)
1274 return false; 1274 return false;
1275 1275 if (next->opnum == OP_ILLEGAL)
1276 return false;
1276 nextd = OPDESC(next); 1277 nextd = OPDESC(next);
1277 /* 1278 /*
1278 * Rest of 2.6.3.1.1: certain operations will return WRONGSEC 1279 * Rest of 2.6.3.1.1: certain operations will return WRONGSEC
@@ -1589,7 +1590,8 @@ static inline u32 nfsd4_rename_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op
1589static inline u32 nfsd4_sequence_rsize(struct svc_rqst *rqstp, 1590static inline u32 nfsd4_sequence_rsize(struct svc_rqst *rqstp,
1590 struct nfsd4_op *op) 1591 struct nfsd4_op *op)
1591{ 1592{
1592 return NFS4_MAX_SESSIONID_LEN + 20; 1593 return (op_encode_hdr_size
1594 + XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN) + 5) * sizeof(__be32);
1593} 1595}
1594 1596
1595static inline u32 nfsd4_setattr_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op) 1597static inline u32 nfsd4_setattr_rsize(struct svc_rqst *rqstp, struct nfsd4_op *op)
@@ -1893,6 +1895,7 @@ static struct nfsd4_operation nfsd4_ops[] = {
1893 .op_func = (nfsd4op_func)nfsd4_sequence, 1895 .op_func = (nfsd4op_func)nfsd4_sequence,
1894 .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP, 1896 .op_flags = ALLOWED_WITHOUT_FH | ALLOWED_AS_FIRST_OP,
1895 .op_name = "OP_SEQUENCE", 1897 .op_name = "OP_SEQUENCE",
1898 .op_rsize_bop = (nfsd4op_rsize)nfsd4_sequence_rsize,
1896 }, 1899 },
1897 [OP_DESTROY_CLIENTID] = { 1900 [OP_DESTROY_CLIENTID] = {
1898 .op_func = (nfsd4op_func)nfsd4_destroy_clientid, 1901 .op_func = (nfsd4op_func)nfsd4_destroy_clientid,
diff --git a/fs/open.c b/fs/open.c
index d6fd3acde134..de92c13b58be 100644
--- a/fs/open.c
+++ b/fs/open.c
@@ -823,8 +823,7 @@ struct file *dentry_open(const struct path *path, int flags,
823 f = get_empty_filp(); 823 f = get_empty_filp();
824 if (!IS_ERR(f)) { 824 if (!IS_ERR(f)) {
825 f->f_flags = flags; 825 f->f_flags = flags;
826 f->f_path = *path; 826 error = vfs_open(path, f, cred);
827 error = do_dentry_open(f, NULL, cred);
828 if (!error) { 827 if (!error) {
829 /* from now on we need fput() to dispose of f */ 828 /* from now on we need fput() to dispose of f */
830 error = open_check_o_direct(f); 829 error = open_check_o_direct(f);
@@ -841,6 +840,26 @@ struct file *dentry_open(const struct path *path, int flags,
841} 840}
842EXPORT_SYMBOL(dentry_open); 841EXPORT_SYMBOL(dentry_open);
843 842
843/**
844 * vfs_open - open the file at the given path
845 * @path: path to open
846 * @filp: newly allocated file with f_flag initialized
847 * @cred: credentials to use
848 */
849int vfs_open(const struct path *path, struct file *filp,
850 const struct cred *cred)
851{
852 struct inode *inode = path->dentry->d_inode;
853
854 if (inode->i_op->dentry_open)
855 return inode->i_op->dentry_open(path->dentry, filp, cred);
856 else {
857 filp->f_path = *path;
858 return do_dentry_open(filp, NULL, cred);
859 }
860}
861EXPORT_SYMBOL(vfs_open);
862
844static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op) 863static inline int build_open_flags(int flags, umode_t mode, struct open_flags *op)
845{ 864{
846 int lookup_flags = 0; 865 int lookup_flags = 0;
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig
new file mode 100644
index 000000000000..e60125976873
--- /dev/null
+++ b/fs/overlayfs/Kconfig
@@ -0,0 +1,10 @@
1config OVERLAYFS_FS
2 tristate "Overlay filesystem support"
3 help
4 An overlay filesystem combines two filesystems - an 'upper' filesystem
5 and a 'lower' filesystem. When a name exists in both filesystems, the
6 object in the 'upper' filesystem is visible while the object in the
7 'lower' filesystem is either hidden or, in the case of directories,
8 merged with the 'upper' object.
9
10 For more information see Documentation/filesystems/overlayfs.txt
diff --git a/fs/overlayfs/Makefile b/fs/overlayfs/Makefile
new file mode 100644
index 000000000000..8f91889480d0
--- /dev/null
+++ b/fs/overlayfs/Makefile
@@ -0,0 +1,7 @@
1#
2# Makefile for the overlay filesystem.
3#
4
5obj-$(CONFIG_OVERLAYFS_FS) += overlayfs.o
6
7overlayfs-objs := super.o inode.o dir.o readdir.o copy_up.o
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
new file mode 100644
index 000000000000..ea10a8719107
--- /dev/null
+++ b/fs/overlayfs/copy_up.c
@@ -0,0 +1,414 @@
1/*
2 *
3 * Copyright (C) 2011 Novell Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/fs.h>
11#include <linux/slab.h>
12#include <linux/file.h>
13#include <linux/splice.h>
14#include <linux/xattr.h>
15#include <linux/security.h>
16#include <linux/uaccess.h>
17#include <linux/sched.h>
18#include <linux/namei.h>
19#include "overlayfs.h"
20
21#define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
22
23int ovl_copy_xattr(struct dentry *old, struct dentry *new)
24{
25 ssize_t list_size, size;
26 char *buf, *name, *value;
27 int error;
28
29 if (!old->d_inode->i_op->getxattr ||
30 !new->d_inode->i_op->getxattr)
31 return 0;
32
33 list_size = vfs_listxattr(old, NULL, 0);
34 if (list_size <= 0) {
35 if (list_size == -EOPNOTSUPP)
36 return 0;
37 return list_size;
38 }
39
40 buf = kzalloc(list_size, GFP_KERNEL);
41 if (!buf)
42 return -ENOMEM;
43
44 error = -ENOMEM;
45 value = kmalloc(XATTR_SIZE_MAX, GFP_KERNEL);
46 if (!value)
47 goto out;
48
49 list_size = vfs_listxattr(old, buf, list_size);
50 if (list_size <= 0) {
51 error = list_size;
52 goto out_free_value;
53 }
54
55 for (name = buf; name < (buf + list_size); name += strlen(name) + 1) {
56 size = vfs_getxattr(old, name, value, XATTR_SIZE_MAX);
57 if (size <= 0) {
58 error = size;
59 goto out_free_value;
60 }
61 error = vfs_setxattr(new, name, value, size, 0);
62 if (error)
63 goto out_free_value;
64 }
65
66out_free_value:
67 kfree(value);
68out:
69 kfree(buf);
70 return error;
71}
72
73static int ovl_copy_up_data(struct path *old, struct path *new, loff_t len)
74{
75 struct file *old_file;
76 struct file *new_file;
77 loff_t old_pos = 0;
78 loff_t new_pos = 0;
79 int error = 0;
80
81 if (len == 0)
82 return 0;
83
84 old_file = ovl_path_open(old, O_RDONLY);
85 if (IS_ERR(old_file))
86 return PTR_ERR(old_file);
87
88 new_file = ovl_path_open(new, O_WRONLY);
89 if (IS_ERR(new_file)) {
90 error = PTR_ERR(new_file);
91 goto out_fput;
92 }
93
94 /* FIXME: copy up sparse files efficiently */
95 while (len) {
96 size_t this_len = OVL_COPY_UP_CHUNK_SIZE;
97 long bytes;
98
99 if (len < this_len)
100 this_len = len;
101
102 if (signal_pending_state(TASK_KILLABLE, current)) {
103 error = -EINTR;
104 break;
105 }
106
107 bytes = do_splice_direct(old_file, &old_pos,
108 new_file, &new_pos,
109 this_len, SPLICE_F_MOVE);
110 if (bytes <= 0) {
111 error = bytes;
112 break;
113 }
114 WARN_ON(old_pos != new_pos);
115
116 len -= bytes;
117 }
118
119 fput(new_file);
120out_fput:
121 fput(old_file);
122 return error;
123}
124
125static char *ovl_read_symlink(struct dentry *realdentry)
126{
127 int res;
128 char *buf;
129 struct inode *inode = realdentry->d_inode;
130 mm_segment_t old_fs;
131
132 res = -EINVAL;
133 if (!inode->i_op->readlink)
134 goto err;
135
136 res = -ENOMEM;
137 buf = (char *) __get_free_page(GFP_KERNEL);
138 if (!buf)
139 goto err;
140
141 old_fs = get_fs();
142 set_fs(get_ds());
143 /* The cast to a user pointer is valid due to the set_fs() */
144 res = inode->i_op->readlink(realdentry,
145 (char __user *)buf, PAGE_SIZE - 1);
146 set_fs(old_fs);
147 if (res < 0) {
148 free_page((unsigned long) buf);
149 goto err;
150 }
151 buf[res] = '\0';
152
153 return buf;
154
155err:
156 return ERR_PTR(res);
157}
158
159static int ovl_set_timestamps(struct dentry *upperdentry, struct kstat *stat)
160{
161 struct iattr attr = {
162 .ia_valid =
163 ATTR_ATIME | ATTR_MTIME | ATTR_ATIME_SET | ATTR_MTIME_SET,
164 .ia_atime = stat->atime,
165 .ia_mtime = stat->mtime,
166 };
167
168 return notify_change(upperdentry, &attr, NULL);
169}
170
171int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
172{
173 int err = 0;
174
175 if (!S_ISLNK(stat->mode)) {
176 struct iattr attr = {
177 .ia_valid = ATTR_MODE,
178 .ia_mode = stat->mode,
179 };
180 err = notify_change(upperdentry, &attr, NULL);
181 }
182 if (!err) {
183 struct iattr attr = {
184 .ia_valid = ATTR_UID | ATTR_GID,
185 .ia_uid = stat->uid,
186 .ia_gid = stat->gid,
187 };
188 err = notify_change(upperdentry, &attr, NULL);
189 }
190 if (!err)
191 ovl_set_timestamps(upperdentry, stat);
192
193 return err;
194
195}
196
197static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
198 struct dentry *dentry, struct path *lowerpath,
199 struct kstat *stat, struct iattr *attr,
200 const char *link)
201{
202 struct inode *wdir = workdir->d_inode;
203 struct inode *udir = upperdir->d_inode;
204 struct dentry *newdentry = NULL;
205 struct dentry *upper = NULL;
206 umode_t mode = stat->mode;
207 int err;
208
209 newdentry = ovl_lookup_temp(workdir, dentry);
210 err = PTR_ERR(newdentry);
211 if (IS_ERR(newdentry))
212 goto out;
213
214 upper = lookup_one_len(dentry->d_name.name, upperdir,
215 dentry->d_name.len);
216 err = PTR_ERR(upper);
217 if (IS_ERR(upper))
218 goto out1;
219
220 /* Can't properly set mode on creation because of the umask */
221 stat->mode &= S_IFMT;
222 err = ovl_create_real(wdir, newdentry, stat, link, NULL, true);
223 stat->mode = mode;
224 if (err)
225 goto out2;
226
227 if (S_ISREG(stat->mode)) {
228 struct path upperpath;
229 ovl_path_upper(dentry, &upperpath);
230 BUG_ON(upperpath.dentry != NULL);
231 upperpath.dentry = newdentry;
232
233 err = ovl_copy_up_data(lowerpath, &upperpath, stat->size);
234 if (err)
235 goto out_cleanup;
236 }
237
238 err = ovl_copy_xattr(lowerpath->dentry, newdentry);
239 if (err)
240 goto out_cleanup;
241
242 mutex_lock(&newdentry->d_inode->i_mutex);
243 err = ovl_set_attr(newdentry, stat);
244 if (!err && attr)
245 err = notify_change(newdentry, attr, NULL);
246 mutex_unlock(&newdentry->d_inode->i_mutex);
247 if (err)
248 goto out_cleanup;
249
250 err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
251 if (err)
252 goto out_cleanup;
253
254 ovl_dentry_update(dentry, newdentry);
255 newdentry = NULL;
256
257 /*
258 * Non-directores become opaque when copied up.
259 */
260 if (!S_ISDIR(stat->mode))
261 ovl_dentry_set_opaque(dentry, true);
262out2:
263 dput(upper);
264out1:
265 dput(newdentry);
266out:
267 return err;
268
269out_cleanup:
270 ovl_cleanup(wdir, newdentry);
271 goto out;
272}
273
274/*
275 * Copy up a single dentry
276 *
277 * Directory renames only allowed on "pure upper" (already created on
278 * upper filesystem, never copied up). Directories which are on lower or
279 * are merged may not be renamed. For these -EXDEV is returned and
280 * userspace has to deal with it. This means, when copying up a
281 * directory we can rely on it and ancestors being stable.
282 *
283 * Non-directory renames start with copy up of source if necessary. The
284 * actual rename will only proceed once the copy up was successful. Copy
285 * up uses upper parent i_mutex for exclusion. Since rename can change
286 * d_parent it is possible that the copy up will lock the old parent. At
287 * that point the file will have already been copied up anyway.
288 */
289int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
290 struct path *lowerpath, struct kstat *stat,
291 struct iattr *attr)
292{
293 struct dentry *workdir = ovl_workdir(dentry);
294 int err;
295 struct kstat pstat;
296 struct path parentpath;
297 struct dentry *upperdir;
298 struct dentry *upperdentry;
299 const struct cred *old_cred;
300 struct cred *override_cred;
301 char *link = NULL;
302
303 ovl_path_upper(parent, &parentpath);
304 upperdir = parentpath.dentry;
305
306 err = vfs_getattr(&parentpath, &pstat);
307 if (err)
308 return err;
309
310 if (S_ISLNK(stat->mode)) {
311 link = ovl_read_symlink(lowerpath->dentry);
312 if (IS_ERR(link))
313 return PTR_ERR(link);
314 }
315
316 err = -ENOMEM;
317 override_cred = prepare_creds();
318 if (!override_cred)
319 goto out_free_link;
320
321 override_cred->fsuid = stat->uid;
322 override_cred->fsgid = stat->gid;
323 /*
324 * CAP_SYS_ADMIN for copying up extended attributes
325 * CAP_DAC_OVERRIDE for create
326 * CAP_FOWNER for chmod, timestamp update
327 * CAP_FSETID for chmod
328 * CAP_CHOWN for chown
329 * CAP_MKNOD for mknod
330 */
331 cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
332 cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
333 cap_raise(override_cred->cap_effective, CAP_FOWNER);
334 cap_raise(override_cred->cap_effective, CAP_FSETID);
335 cap_raise(override_cred->cap_effective, CAP_CHOWN);
336 cap_raise(override_cred->cap_effective, CAP_MKNOD);
337 old_cred = override_creds(override_cred);
338
339 err = -EIO;
340 if (lock_rename(workdir, upperdir) != NULL) {
341 pr_err("overlayfs: failed to lock workdir+upperdir\n");
342 goto out_unlock;
343 }
344 upperdentry = ovl_dentry_upper(dentry);
345 if (upperdentry) {
346 unlock_rename(workdir, upperdir);
347 err = 0;
348 /* Raced with another copy-up? Do the setattr here */
349 if (attr) {
350 mutex_lock(&upperdentry->d_inode->i_mutex);
351 err = notify_change(upperdentry, attr, NULL);
352 mutex_unlock(&upperdentry->d_inode->i_mutex);
353 }
354 goto out_put_cred;
355 }
356
357 err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
358 stat, attr, link);
359 if (!err) {
360 /* Restore timestamps on parent (best effort) */
361 ovl_set_timestamps(upperdir, &pstat);
362 }
363out_unlock:
364 unlock_rename(workdir, upperdir);
365out_put_cred:
366 revert_creds(old_cred);
367 put_cred(override_cred);
368
369out_free_link:
370 if (link)
371 free_page((unsigned long) link);
372
373 return err;
374}
375
376int ovl_copy_up(struct dentry *dentry)
377{
378 int err;
379
380 err = 0;
381 while (!err) {
382 struct dentry *next;
383 struct dentry *parent;
384 struct path lowerpath;
385 struct kstat stat;
386 enum ovl_path_type type = ovl_path_type(dentry);
387
388 if (type != OVL_PATH_LOWER)
389 break;
390
391 next = dget(dentry);
392 /* find the topmost dentry not yet copied up */
393 for (;;) {
394 parent = dget_parent(next);
395
396 type = ovl_path_type(parent);
397 if (type != OVL_PATH_LOWER)
398 break;
399
400 dput(next);
401 next = parent;
402 }
403
404 ovl_path_lower(next, &lowerpath);
405 err = vfs_getattr(&lowerpath, &stat);
406 if (!err)
407 err = ovl_copy_up_one(parent, next, &lowerpath, &stat, NULL);
408
409 dput(parent);
410 dput(next);
411 }
412
413 return err;
414}
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
new file mode 100644
index 000000000000..15cd91ad9940
--- /dev/null
+++ b/fs/overlayfs/dir.c
@@ -0,0 +1,921 @@
1/*
2 *
3 * Copyright (C) 2011 Novell Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/fs.h>
11#include <linux/namei.h>
12#include <linux/xattr.h>
13#include <linux/security.h>
14#include <linux/cred.h>
15#include "overlayfs.h"
16
17void ovl_cleanup(struct inode *wdir, struct dentry *wdentry)
18{
19 int err;
20
21 dget(wdentry);
22 if (S_ISDIR(wdentry->d_inode->i_mode))
23 err = ovl_do_rmdir(wdir, wdentry);
24 else
25 err = ovl_do_unlink(wdir, wdentry);
26 dput(wdentry);
27
28 if (err) {
29 pr_err("overlayfs: cleanup of '%pd2' failed (%i)\n",
30 wdentry, err);
31 }
32}
33
34struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry)
35{
36 struct dentry *temp;
37 char name[20];
38
39 snprintf(name, sizeof(name), "#%lx", (unsigned long) dentry);
40
41 temp = lookup_one_len(name, workdir, strlen(name));
42 if (!IS_ERR(temp) && temp->d_inode) {
43 pr_err("overlayfs: workdir/%s already exists\n", name);
44 dput(temp);
45 temp = ERR_PTR(-EIO);
46 }
47
48 return temp;
49}
50
51/* caller holds i_mutex on workdir */
52static struct dentry *ovl_whiteout(struct dentry *workdir,
53 struct dentry *dentry)
54{
55 int err;
56 struct dentry *whiteout;
57 struct inode *wdir = workdir->d_inode;
58
59 whiteout = ovl_lookup_temp(workdir, dentry);
60 if (IS_ERR(whiteout))
61 return whiteout;
62
63 err = ovl_do_whiteout(wdir, whiteout);
64 if (err) {
65 dput(whiteout);
66 whiteout = ERR_PTR(err);
67 }
68
69 return whiteout;
70}
71
72int ovl_create_real(struct inode *dir, struct dentry *newdentry,
73 struct kstat *stat, const char *link,
74 struct dentry *hardlink, bool debug)
75{
76 int err;
77
78 if (newdentry->d_inode)
79 return -ESTALE;
80
81 if (hardlink) {
82 err = ovl_do_link(hardlink, dir, newdentry, debug);
83 } else {
84 switch (stat->mode & S_IFMT) {
85 case S_IFREG:
86 err = ovl_do_create(dir, newdentry, stat->mode, debug);
87 break;
88
89 case S_IFDIR:
90 err = ovl_do_mkdir(dir, newdentry, stat->mode, debug);
91 break;
92
93 case S_IFCHR:
94 case S_IFBLK:
95 case S_IFIFO:
96 case S_IFSOCK:
97 err = ovl_do_mknod(dir, newdentry,
98 stat->mode, stat->rdev, debug);
99 break;
100
101 case S_IFLNK:
102 err = ovl_do_symlink(dir, newdentry, link, debug);
103 break;
104
105 default:
106 err = -EPERM;
107 }
108 }
109 if (!err && WARN_ON(!newdentry->d_inode)) {
110 /*
111 * Not quite sure if non-instantiated dentry is legal or not.
112 * VFS doesn't seem to care so check and warn here.
113 */
114 err = -ENOENT;
115 }
116 return err;
117}
118
119static int ovl_set_opaque(struct dentry *upperdentry)
120{
121 return ovl_do_setxattr(upperdentry, ovl_opaque_xattr, "y", 1, 0);
122}
123
124static void ovl_remove_opaque(struct dentry *upperdentry)
125{
126 int err;
127
128 err = ovl_do_removexattr(upperdentry, ovl_opaque_xattr);
129 if (err) {
130 pr_warn("overlayfs: failed to remove opaque from '%s' (%i)\n",
131 upperdentry->d_name.name, err);
132 }
133}
134
135static int ovl_dir_getattr(struct vfsmount *mnt, struct dentry *dentry,
136 struct kstat *stat)
137{
138 int err;
139 enum ovl_path_type type;
140 struct path realpath;
141
142 type = ovl_path_real(dentry, &realpath);
143 err = vfs_getattr(&realpath, stat);
144 if (err)
145 return err;
146
147 stat->dev = dentry->d_sb->s_dev;
148 stat->ino = dentry->d_inode->i_ino;
149
150 /*
151 * It's probably not worth it to count subdirs to get the
152 * correct link count. nlink=1 seems to pacify 'find' and
153 * other utilities.
154 */
155 if (type == OVL_PATH_MERGE)
156 stat->nlink = 1;
157
158 return 0;
159}
160
161static int ovl_create_upper(struct dentry *dentry, struct inode *inode,
162 struct kstat *stat, const char *link,
163 struct dentry *hardlink)
164{
165 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
166 struct inode *udir = upperdir->d_inode;
167 struct dentry *newdentry;
168 int err;
169
170 mutex_lock_nested(&udir->i_mutex, I_MUTEX_PARENT);
171 newdentry = lookup_one_len(dentry->d_name.name, upperdir,
172 dentry->d_name.len);
173 err = PTR_ERR(newdentry);
174 if (IS_ERR(newdentry))
175 goto out_unlock;
176 err = ovl_create_real(udir, newdentry, stat, link, hardlink, false);
177 if (err)
178 goto out_dput;
179
180 ovl_dentry_version_inc(dentry->d_parent);
181 ovl_dentry_update(dentry, newdentry);
182 ovl_copyattr(newdentry->d_inode, inode);
183 d_instantiate(dentry, inode);
184 newdentry = NULL;
185out_dput:
186 dput(newdentry);
187out_unlock:
188 mutex_unlock(&udir->i_mutex);
189 return err;
190}
191
192static int ovl_lock_rename_workdir(struct dentry *workdir,
193 struct dentry *upperdir)
194{
195 /* Workdir should not be the same as upperdir */
196 if (workdir == upperdir)
197 goto err;
198
199 /* Workdir should not be subdir of upperdir and vice versa */
200 if (lock_rename(workdir, upperdir) != NULL)
201 goto err_unlock;
202
203 return 0;
204
205err_unlock:
206 unlock_rename(workdir, upperdir);
207err:
208 pr_err("overlayfs: failed to lock workdir+upperdir\n");
209 return -EIO;
210}
211
212static struct dentry *ovl_clear_empty(struct dentry *dentry,
213 struct list_head *list)
214{
215 struct dentry *workdir = ovl_workdir(dentry);
216 struct inode *wdir = workdir->d_inode;
217 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
218 struct inode *udir = upperdir->d_inode;
219 struct path upperpath;
220 struct dentry *upper;
221 struct dentry *opaquedir;
222 struct kstat stat;
223 int err;
224
225 err = ovl_lock_rename_workdir(workdir, upperdir);
226 if (err)
227 goto out;
228
229 ovl_path_upper(dentry, &upperpath);
230 err = vfs_getattr(&upperpath, &stat);
231 if (err)
232 goto out_unlock;
233
234 err = -ESTALE;
235 if (!S_ISDIR(stat.mode))
236 goto out_unlock;
237 upper = upperpath.dentry;
238 if (upper->d_parent->d_inode != udir)
239 goto out_unlock;
240
241 opaquedir = ovl_lookup_temp(workdir, dentry);
242 err = PTR_ERR(opaquedir);
243 if (IS_ERR(opaquedir))
244 goto out_unlock;
245
246 err = ovl_create_real(wdir, opaquedir, &stat, NULL, NULL, true);
247 if (err)
248 goto out_dput;
249
250 err = ovl_copy_xattr(upper, opaquedir);
251 if (err)
252 goto out_cleanup;
253
254 err = ovl_set_opaque(opaquedir);
255 if (err)
256 goto out_cleanup;
257
258 mutex_lock(&opaquedir->d_inode->i_mutex);
259 err = ovl_set_attr(opaquedir, &stat);
260 mutex_unlock(&opaquedir->d_inode->i_mutex);
261 if (err)
262 goto out_cleanup;
263
264 err = ovl_do_rename(wdir, opaquedir, udir, upper, RENAME_EXCHANGE);
265 if (err)
266 goto out_cleanup;
267
268 ovl_cleanup_whiteouts(upper, list);
269 ovl_cleanup(wdir, upper);
270 unlock_rename(workdir, upperdir);
271
272 /* dentry's upper doesn't match now, get rid of it */
273 d_drop(dentry);
274
275 return opaquedir;
276
277out_cleanup:
278 ovl_cleanup(wdir, opaquedir);
279out_dput:
280 dput(opaquedir);
281out_unlock:
282 unlock_rename(workdir, upperdir);
283out:
284 return ERR_PTR(err);
285}
286
287static struct dentry *ovl_check_empty_and_clear(struct dentry *dentry,
288 enum ovl_path_type type)
289{
290 int err;
291 struct dentry *ret = NULL;
292 LIST_HEAD(list);
293
294 err = ovl_check_empty_dir(dentry, &list);
295 if (err)
296 ret = ERR_PTR(err);
297 else if (type == OVL_PATH_MERGE)
298 ret = ovl_clear_empty(dentry, &list);
299
300 ovl_cache_free(&list);
301
302 return ret;
303}
304
305static int ovl_create_over_whiteout(struct dentry *dentry, struct inode *inode,
306 struct kstat *stat, const char *link,
307 struct dentry *hardlink)
308{
309 struct dentry *workdir = ovl_workdir(dentry);
310 struct inode *wdir = workdir->d_inode;
311 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
312 struct inode *udir = upperdir->d_inode;
313 struct dentry *upper;
314 struct dentry *newdentry;
315 int err;
316
317 err = ovl_lock_rename_workdir(workdir, upperdir);
318 if (err)
319 goto out;
320
321 newdentry = ovl_lookup_temp(workdir, dentry);
322 err = PTR_ERR(newdentry);
323 if (IS_ERR(newdentry))
324 goto out_unlock;
325
326 upper = lookup_one_len(dentry->d_name.name, upperdir,
327 dentry->d_name.len);
328 err = PTR_ERR(upper);
329 if (IS_ERR(upper))
330 goto out_dput;
331
332 err = ovl_create_real(wdir, newdentry, stat, link, hardlink, true);
333 if (err)
334 goto out_dput2;
335
336 if (S_ISDIR(stat->mode)) {
337 err = ovl_set_opaque(newdentry);
338 if (err)
339 goto out_cleanup;
340
341 err = ovl_do_rename(wdir, newdentry, udir, upper,
342 RENAME_EXCHANGE);
343 if (err)
344 goto out_cleanup;
345
346 ovl_cleanup(wdir, upper);
347 } else {
348 err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
349 if (err)
350 goto out_cleanup;
351 }
352 ovl_dentry_version_inc(dentry->d_parent);
353 ovl_dentry_update(dentry, newdentry);
354 ovl_copyattr(newdentry->d_inode, inode);
355 d_instantiate(dentry, inode);
356 newdentry = NULL;
357out_dput2:
358 dput(upper);
359out_dput:
360 dput(newdentry);
361out_unlock:
362 unlock_rename(workdir, upperdir);
363out:
364 return err;
365
366out_cleanup:
367 ovl_cleanup(wdir, newdentry);
368 goto out_dput2;
369}
370
371static int ovl_create_or_link(struct dentry *dentry, int mode, dev_t rdev,
372 const char *link, struct dentry *hardlink)
373{
374 int err;
375 struct inode *inode;
376 struct kstat stat = {
377 .mode = mode,
378 .rdev = rdev,
379 };
380
381 err = -ENOMEM;
382 inode = ovl_new_inode(dentry->d_sb, mode, dentry->d_fsdata);
383 if (!inode)
384 goto out;
385
386 err = ovl_copy_up(dentry->d_parent);
387 if (err)
388 goto out_iput;
389
390 if (!ovl_dentry_is_opaque(dentry)) {
391 err = ovl_create_upper(dentry, inode, &stat, link, hardlink);
392 } else {
393 const struct cred *old_cred;
394 struct cred *override_cred;
395
396 err = -ENOMEM;
397 override_cred = prepare_creds();
398 if (!override_cred)
399 goto out_iput;
400
401 /*
402 * CAP_SYS_ADMIN for setting opaque xattr
403 * CAP_DAC_OVERRIDE for create in workdir, rename
404 * CAP_FOWNER for removing whiteout from sticky dir
405 */
406 cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
407 cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
408 cap_raise(override_cred->cap_effective, CAP_FOWNER);
409 old_cred = override_creds(override_cred);
410
411 err = ovl_create_over_whiteout(dentry, inode, &stat, link,
412 hardlink);
413
414 revert_creds(old_cred);
415 put_cred(override_cred);
416 }
417
418 if (!err)
419 inode = NULL;
420out_iput:
421 iput(inode);
422out:
423 return err;
424}
425
426static int ovl_create_object(struct dentry *dentry, int mode, dev_t rdev,
427 const char *link)
428{
429 int err;
430
431 err = ovl_want_write(dentry);
432 if (!err) {
433 err = ovl_create_or_link(dentry, mode, rdev, link, NULL);
434 ovl_drop_write(dentry);
435 }
436
437 return err;
438}
439
440static int ovl_create(struct inode *dir, struct dentry *dentry, umode_t mode,
441 bool excl)
442{
443 return ovl_create_object(dentry, (mode & 07777) | S_IFREG, 0, NULL);
444}
445
446static int ovl_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
447{
448 return ovl_create_object(dentry, (mode & 07777) | S_IFDIR, 0, NULL);
449}
450
451static int ovl_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
452 dev_t rdev)
453{
454 /* Don't allow creation of "whiteout" on overlay */
455 if (S_ISCHR(mode) && rdev == WHITEOUT_DEV)
456 return -EPERM;
457
458 return ovl_create_object(dentry, mode, rdev, NULL);
459}
460
461static int ovl_symlink(struct inode *dir, struct dentry *dentry,
462 const char *link)
463{
464 return ovl_create_object(dentry, S_IFLNK, 0, link);
465}
466
467static int ovl_link(struct dentry *old, struct inode *newdir,
468 struct dentry *new)
469{
470 int err;
471 struct dentry *upper;
472
473 err = ovl_want_write(old);
474 if (err)
475 goto out;
476
477 err = ovl_copy_up(old);
478 if (err)
479 goto out_drop_write;
480
481 upper = ovl_dentry_upper(old);
482 err = ovl_create_or_link(new, upper->d_inode->i_mode, 0, NULL, upper);
483
484out_drop_write:
485 ovl_drop_write(old);
486out:
487 return err;
488}
489
490static int ovl_remove_and_whiteout(struct dentry *dentry,
491 enum ovl_path_type type, bool is_dir)
492{
493 struct dentry *workdir = ovl_workdir(dentry);
494 struct inode *wdir = workdir->d_inode;
495 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
496 struct inode *udir = upperdir->d_inode;
497 struct dentry *whiteout;
498 struct dentry *upper;
499 struct dentry *opaquedir = NULL;
500 int err;
501
502 if (is_dir) {
503 opaquedir = ovl_check_empty_and_clear(dentry, type);
504 err = PTR_ERR(opaquedir);
505 if (IS_ERR(opaquedir))
506 goto out;
507 }
508
509 err = ovl_lock_rename_workdir(workdir, upperdir);
510 if (err)
511 goto out_dput;
512
513 whiteout = ovl_whiteout(workdir, dentry);
514 err = PTR_ERR(whiteout);
515 if (IS_ERR(whiteout))
516 goto out_unlock;
517
518 if (type == OVL_PATH_LOWER) {
519 upper = lookup_one_len(dentry->d_name.name, upperdir,
520 dentry->d_name.len);
521 err = PTR_ERR(upper);
522 if (IS_ERR(upper))
523 goto kill_whiteout;
524
525 err = ovl_do_rename(wdir, whiteout, udir, upper, 0);
526 dput(upper);
527 if (err)
528 goto kill_whiteout;
529 } else {
530 int flags = 0;
531
532 upper = ovl_dentry_upper(dentry);
533 if (opaquedir)
534 upper = opaquedir;
535 err = -ESTALE;
536 if (upper->d_parent != upperdir)
537 goto kill_whiteout;
538
539 if (is_dir)
540 flags |= RENAME_EXCHANGE;
541
542 err = ovl_do_rename(wdir, whiteout, udir, upper, flags);
543 if (err)
544 goto kill_whiteout;
545
546 if (is_dir)
547 ovl_cleanup(wdir, upper);
548 }
549 ovl_dentry_version_inc(dentry->d_parent);
550out_d_drop:
551 d_drop(dentry);
552 dput(whiteout);
553out_unlock:
554 unlock_rename(workdir, upperdir);
555out_dput:
556 dput(opaquedir);
557out:
558 return err;
559
560kill_whiteout:
561 ovl_cleanup(wdir, whiteout);
562 goto out_d_drop;
563}
564
565static int ovl_remove_upper(struct dentry *dentry, bool is_dir)
566{
567 struct dentry *upperdir = ovl_dentry_upper(dentry->d_parent);
568 struct inode *dir = upperdir->d_inode;
569 struct dentry *upper = ovl_dentry_upper(dentry);
570 int err;
571
572 mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
573 err = -ESTALE;
574 if (upper->d_parent == upperdir) {
575 /* Don't let d_delete() think it can reset d_inode */
576 dget(upper);
577 if (is_dir)
578 err = vfs_rmdir(dir, upper);
579 else
580 err = vfs_unlink(dir, upper, NULL);
581 dput(upper);
582 ovl_dentry_version_inc(dentry->d_parent);
583 }
584
585 /*
586 * Keeping this dentry hashed would mean having to release
587 * upperpath/lowerpath, which could only be done if we are the
588 * sole user of this dentry. Too tricky... Just unhash for
589 * now.
590 */
591 d_drop(dentry);
592 mutex_unlock(&dir->i_mutex);
593
594 return err;
595}
596
597static inline int ovl_check_sticky(struct dentry *dentry)
598{
599 struct inode *dir = ovl_dentry_real(dentry->d_parent)->d_inode;
600 struct inode *inode = ovl_dentry_real(dentry)->d_inode;
601
602 if (check_sticky(dir, inode))
603 return -EPERM;
604
605 return 0;
606}
607
608static int ovl_do_remove(struct dentry *dentry, bool is_dir)
609{
610 enum ovl_path_type type;
611 int err;
612
613 err = ovl_check_sticky(dentry);
614 if (err)
615 goto out;
616
617 err = ovl_want_write(dentry);
618 if (err)
619 goto out;
620
621 err = ovl_copy_up(dentry->d_parent);
622 if (err)
623 goto out_drop_write;
624
625 type = ovl_path_type(dentry);
626 if (type == OVL_PATH_PURE_UPPER) {
627 err = ovl_remove_upper(dentry, is_dir);
628 } else {
629 const struct cred *old_cred;
630 struct cred *override_cred;
631
632 err = -ENOMEM;
633 override_cred = prepare_creds();
634 if (!override_cred)
635 goto out_drop_write;
636
637 /*
638 * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir
639 * CAP_DAC_OVERRIDE for create in workdir, rename
640 * CAP_FOWNER for removing whiteout from sticky dir
641 * CAP_FSETID for chmod of opaque dir
642 * CAP_CHOWN for chown of opaque dir
643 */
644 cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
645 cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
646 cap_raise(override_cred->cap_effective, CAP_FOWNER);
647 cap_raise(override_cred->cap_effective, CAP_FSETID);
648 cap_raise(override_cred->cap_effective, CAP_CHOWN);
649 old_cred = override_creds(override_cred);
650
651 err = ovl_remove_and_whiteout(dentry, type, is_dir);
652
653 revert_creds(old_cred);
654 put_cred(override_cred);
655 }
656out_drop_write:
657 ovl_drop_write(dentry);
658out:
659 return err;
660}
661
662static int ovl_unlink(struct inode *dir, struct dentry *dentry)
663{
664 return ovl_do_remove(dentry, false);
665}
666
667static int ovl_rmdir(struct inode *dir, struct dentry *dentry)
668{
669 return ovl_do_remove(dentry, true);
670}
671
672static int ovl_rename2(struct inode *olddir, struct dentry *old,
673 struct inode *newdir, struct dentry *new,
674 unsigned int flags)
675{
676 int err;
677 enum ovl_path_type old_type;
678 enum ovl_path_type new_type;
679 struct dentry *old_upperdir;
680 struct dentry *new_upperdir;
681 struct dentry *olddentry;
682 struct dentry *newdentry;
683 struct dentry *trap;
684 bool old_opaque;
685 bool new_opaque;
686 bool new_create = false;
687 bool cleanup_whiteout = false;
688 bool overwrite = !(flags & RENAME_EXCHANGE);
689 bool is_dir = S_ISDIR(old->d_inode->i_mode);
690 bool new_is_dir = false;
691 struct dentry *opaquedir = NULL;
692 const struct cred *old_cred = NULL;
693 struct cred *override_cred = NULL;
694
695 err = -EINVAL;
696 if (flags & ~(RENAME_EXCHANGE | RENAME_NOREPLACE))
697 goto out;
698
699 flags &= ~RENAME_NOREPLACE;
700
701 err = ovl_check_sticky(old);
702 if (err)
703 goto out;
704
705 /* Don't copy up directory trees */
706 old_type = ovl_path_type(old);
707 err = -EXDEV;
708 if ((old_type == OVL_PATH_LOWER || old_type == OVL_PATH_MERGE) && is_dir)
709 goto out;
710
711 if (new->d_inode) {
712 err = ovl_check_sticky(new);
713 if (err)
714 goto out;
715
716 if (S_ISDIR(new->d_inode->i_mode))
717 new_is_dir = true;
718
719 new_type = ovl_path_type(new);
720 err = -EXDEV;
721 if (!overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir)
722 goto out;
723
724 err = 0;
725 if (new_type == OVL_PATH_LOWER && old_type == OVL_PATH_LOWER) {
726 if (ovl_dentry_lower(old)->d_inode ==
727 ovl_dentry_lower(new)->d_inode)
728 goto out;
729 }
730 if (new_type != OVL_PATH_LOWER && old_type != OVL_PATH_LOWER) {
731 if (ovl_dentry_upper(old)->d_inode ==
732 ovl_dentry_upper(new)->d_inode)
733 goto out;
734 }
735 } else {
736 if (ovl_dentry_is_opaque(new))
737 new_type = OVL_PATH_UPPER;
738 else
739 new_type = OVL_PATH_PURE_UPPER;
740 }
741
742 err = ovl_want_write(old);
743 if (err)
744 goto out;
745
746 err = ovl_copy_up(old);
747 if (err)
748 goto out_drop_write;
749
750 err = ovl_copy_up(new->d_parent);
751 if (err)
752 goto out_drop_write;
753 if (!overwrite) {
754 err = ovl_copy_up(new);
755 if (err)
756 goto out_drop_write;
757 }
758
759 old_opaque = old_type != OVL_PATH_PURE_UPPER;
760 new_opaque = new_type != OVL_PATH_PURE_UPPER;
761
762 if (old_opaque || new_opaque) {
763 err = -ENOMEM;
764 override_cred = prepare_creds();
765 if (!override_cred)
766 goto out_drop_write;
767
768 /*
769 * CAP_SYS_ADMIN for setting xattr on whiteout, opaque dir
770 * CAP_DAC_OVERRIDE for create in workdir
771 * CAP_FOWNER for removing whiteout from sticky dir
772 * CAP_FSETID for chmod of opaque dir
773 * CAP_CHOWN for chown of opaque dir
774 */
775 cap_raise(override_cred->cap_effective, CAP_SYS_ADMIN);
776 cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
777 cap_raise(override_cred->cap_effective, CAP_FOWNER);
778 cap_raise(override_cred->cap_effective, CAP_FSETID);
779 cap_raise(override_cred->cap_effective, CAP_CHOWN);
780 old_cred = override_creds(override_cred);
781 }
782
783 if (overwrite && (new_type == OVL_PATH_LOWER || new_type == OVL_PATH_MERGE) && new_is_dir) {
784 opaquedir = ovl_check_empty_and_clear(new, new_type);
785 err = PTR_ERR(opaquedir);
786 if (IS_ERR(opaquedir)) {
787 opaquedir = NULL;
788 goto out_revert_creds;
789 }
790 }
791
792 if (overwrite) {
793 if (old_opaque) {
794 if (new->d_inode || !new_opaque) {
795 /* Whiteout source */
796 flags |= RENAME_WHITEOUT;
797 } else {
798 /* Switch whiteouts */
799 flags |= RENAME_EXCHANGE;
800 }
801 } else if (is_dir && !new->d_inode && new_opaque) {
802 flags |= RENAME_EXCHANGE;
803 cleanup_whiteout = true;
804 }
805 }
806
807 old_upperdir = ovl_dentry_upper(old->d_parent);
808 new_upperdir = ovl_dentry_upper(new->d_parent);
809
810 trap = lock_rename(new_upperdir, old_upperdir);
811
812 olddentry = ovl_dentry_upper(old);
813 newdentry = ovl_dentry_upper(new);
814 if (newdentry) {
815 if (opaquedir) {
816 newdentry = opaquedir;
817 opaquedir = NULL;
818 } else {
819 dget(newdentry);
820 }
821 } else {
822 new_create = true;
823 newdentry = lookup_one_len(new->d_name.name, new_upperdir,
824 new->d_name.len);
825 err = PTR_ERR(newdentry);
826 if (IS_ERR(newdentry))
827 goto out_unlock;
828 }
829
830 err = -ESTALE;
831 if (olddentry->d_parent != old_upperdir)
832 goto out_dput;
833 if (newdentry->d_parent != new_upperdir)
834 goto out_dput;
835 if (olddentry == trap)
836 goto out_dput;
837 if (newdentry == trap)
838 goto out_dput;
839
840 if (is_dir && !old_opaque && new_opaque) {
841 err = ovl_set_opaque(olddentry);
842 if (err)
843 goto out_dput;
844 }
845 if (!overwrite && new_is_dir && old_opaque && !new_opaque) {
846 err = ovl_set_opaque(newdentry);
847 if (err)
848 goto out_dput;
849 }
850
851 if (old_opaque || new_opaque) {
852 err = ovl_do_rename(old_upperdir->d_inode, olddentry,
853 new_upperdir->d_inode, newdentry,
854 flags);
855 } else {
856 /* No debug for the plain case */
857 BUG_ON(flags & ~RENAME_EXCHANGE);
858 err = vfs_rename(old_upperdir->d_inode, olddentry,
859 new_upperdir->d_inode, newdentry,
860 NULL, flags);
861 }
862
863 if (err) {
864 if (is_dir && !old_opaque && new_opaque)
865 ovl_remove_opaque(olddentry);
866 if (!overwrite && new_is_dir && old_opaque && !new_opaque)
867 ovl_remove_opaque(newdentry);
868 goto out_dput;
869 }
870
871 if (is_dir && old_opaque && !new_opaque)
872 ovl_remove_opaque(olddentry);
873 if (!overwrite && new_is_dir && !old_opaque && new_opaque)
874 ovl_remove_opaque(newdentry);
875
876 if (old_opaque != new_opaque) {
877 ovl_dentry_set_opaque(old, new_opaque);
878 if (!overwrite)
879 ovl_dentry_set_opaque(new, old_opaque);
880 }
881
882 if (cleanup_whiteout)
883 ovl_cleanup(old_upperdir->d_inode, newdentry);
884
885 ovl_dentry_version_inc(old->d_parent);
886 ovl_dentry_version_inc(new->d_parent);
887
888out_dput:
889 dput(newdentry);
890out_unlock:
891 unlock_rename(new_upperdir, old_upperdir);
892out_revert_creds:
893 if (old_opaque || new_opaque) {
894 revert_creds(old_cred);
895 put_cred(override_cred);
896 }
897out_drop_write:
898 ovl_drop_write(old);
899out:
900 dput(opaquedir);
901 return err;
902}
903
904const struct inode_operations ovl_dir_inode_operations = {
905 .lookup = ovl_lookup,
906 .mkdir = ovl_mkdir,
907 .symlink = ovl_symlink,
908 .unlink = ovl_unlink,
909 .rmdir = ovl_rmdir,
910 .rename2 = ovl_rename2,
911 .link = ovl_link,
912 .setattr = ovl_setattr,
913 .create = ovl_create,
914 .mknod = ovl_mknod,
915 .permission = ovl_permission,
916 .getattr = ovl_dir_getattr,
917 .setxattr = ovl_setxattr,
918 .getxattr = ovl_getxattr,
919 .listxattr = ovl_listxattr,
920 .removexattr = ovl_removexattr,
921};
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
new file mode 100644
index 000000000000..af2d18c9fcee
--- /dev/null
+++ b/fs/overlayfs/inode.c
@@ -0,0 +1,425 @@
1/*
2 *
3 * Copyright (C) 2011 Novell Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/fs.h>
11#include <linux/slab.h>
12#include <linux/xattr.h>
13#include "overlayfs.h"
14
15static int ovl_copy_up_last(struct dentry *dentry, struct iattr *attr,
16 bool no_data)
17{
18 int err;
19 struct dentry *parent;
20 struct kstat stat;
21 struct path lowerpath;
22
23 parent = dget_parent(dentry);
24 err = ovl_copy_up(parent);
25 if (err)
26 goto out_dput_parent;
27
28 ovl_path_lower(dentry, &lowerpath);
29 err = vfs_getattr(&lowerpath, &stat);
30 if (err)
31 goto out_dput_parent;
32
33 if (no_data)
34 stat.size = 0;
35
36 err = ovl_copy_up_one(parent, dentry, &lowerpath, &stat, attr);
37
38out_dput_parent:
39 dput(parent);
40 return err;
41}
42
43int ovl_setattr(struct dentry *dentry, struct iattr *attr)
44{
45 int err;
46 struct dentry *upperdentry;
47
48 err = ovl_want_write(dentry);
49 if (err)
50 goto out;
51
52 upperdentry = ovl_dentry_upper(dentry);
53 if (upperdentry) {
54 mutex_lock(&upperdentry->d_inode->i_mutex);
55 err = notify_change(upperdentry, attr, NULL);
56 mutex_unlock(&upperdentry->d_inode->i_mutex);
57 } else {
58 err = ovl_copy_up_last(dentry, attr, false);
59 }
60 ovl_drop_write(dentry);
61out:
62 return err;
63}
64
65static int ovl_getattr(struct vfsmount *mnt, struct dentry *dentry,
66 struct kstat *stat)
67{
68 struct path realpath;
69
70 ovl_path_real(dentry, &realpath);
71 return vfs_getattr(&realpath, stat);
72}
73
74int ovl_permission(struct inode *inode, int mask)
75{
76 struct ovl_entry *oe;
77 struct dentry *alias = NULL;
78 struct inode *realinode;
79 struct dentry *realdentry;
80 bool is_upper;
81 int err;
82
83 if (S_ISDIR(inode->i_mode)) {
84 oe = inode->i_private;
85 } else if (mask & MAY_NOT_BLOCK) {
86 return -ECHILD;
87 } else {
88 /*
89 * For non-directories find an alias and get the info
90 * from there.
91 */
92 alias = d_find_any_alias(inode);
93 if (WARN_ON(!alias))
94 return -ENOENT;
95
96 oe = alias->d_fsdata;
97 }
98
99 realdentry = ovl_entry_real(oe, &is_upper);
100
101 /* Careful in RCU walk mode */
102 realinode = ACCESS_ONCE(realdentry->d_inode);
103 if (!realinode) {
104 WARN_ON(!(mask & MAY_NOT_BLOCK));
105 err = -ENOENT;
106 goto out_dput;
107 }
108
109 if (mask & MAY_WRITE) {
110 umode_t mode = realinode->i_mode;
111
112 /*
113 * Writes will always be redirected to upper layer, so
114 * ignore lower layer being read-only.
115 *
116 * If the overlay itself is read-only then proceed
117 * with the permission check, don't return EROFS.
118 * This will only happen if this is the lower layer of
119 * another overlayfs.
120 *
121 * If upper fs becomes read-only after the overlay was
122 * constructed return EROFS to prevent modification of
123 * upper layer.
124 */
125 err = -EROFS;
126 if (is_upper && !IS_RDONLY(inode) && IS_RDONLY(realinode) &&
127 (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)))
128 goto out_dput;
129 }
130
131 err = __inode_permission(realinode, mask);
132out_dput:
133 dput(alias);
134 return err;
135}
136
137
138struct ovl_link_data {
139 struct dentry *realdentry;
140 void *cookie;
141};
142
143static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd)
144{
145 void *ret;
146 struct dentry *realdentry;
147 struct inode *realinode;
148
149 realdentry = ovl_dentry_real(dentry);
150 realinode = realdentry->d_inode;
151
152 if (WARN_ON(!realinode->i_op->follow_link))
153 return ERR_PTR(-EPERM);
154
155 ret = realinode->i_op->follow_link(realdentry, nd);
156 if (IS_ERR(ret))
157 return ret;
158
159 if (realinode->i_op->put_link) {
160 struct ovl_link_data *data;
161
162 data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL);
163 if (!data) {
164 realinode->i_op->put_link(realdentry, nd, ret);
165 return ERR_PTR(-ENOMEM);
166 }
167 data->realdentry = realdentry;
168 data->cookie = ret;
169
170 return data;
171 } else {
172 return NULL;
173 }
174}
175
176static void ovl_put_link(struct dentry *dentry, struct nameidata *nd, void *c)
177{
178 struct inode *realinode;
179 struct ovl_link_data *data = c;
180
181 if (!data)
182 return;
183
184 realinode = data->realdentry->d_inode;
185 realinode->i_op->put_link(data->realdentry, nd, data->cookie);
186 kfree(data);
187}
188
189static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
190{
191 struct path realpath;
192 struct inode *realinode;
193
194 ovl_path_real(dentry, &realpath);
195 realinode = realpath.dentry->d_inode;
196
197 if (!realinode->i_op->readlink)
198 return -EINVAL;
199
200 touch_atime(&realpath);
201
202 return realinode->i_op->readlink(realpath.dentry, buf, bufsiz);
203}
204
205
206static bool ovl_is_private_xattr(const char *name)
207{
208 return strncmp(name, "trusted.overlay.", 14) == 0;
209}
210
211int ovl_setxattr(struct dentry *dentry, const char *name,
212 const void *value, size_t size, int flags)
213{
214 int err;
215 struct dentry *upperdentry;
216
217 err = ovl_want_write(dentry);
218 if (err)
219 goto out;
220
221 err = -EPERM;
222 if (ovl_is_private_xattr(name))
223 goto out_drop_write;
224
225 err = ovl_copy_up(dentry);
226 if (err)
227 goto out_drop_write;
228
229 upperdentry = ovl_dentry_upper(dentry);
230 err = vfs_setxattr(upperdentry, name, value, size, flags);
231
232out_drop_write:
233 ovl_drop_write(dentry);
234out:
235 return err;
236}
237
238ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
239 void *value, size_t size)
240{
241 if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
242 ovl_is_private_xattr(name))
243 return -ENODATA;
244
245 return vfs_getxattr(ovl_dentry_real(dentry), name, value, size);
246}
247
248ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size)
249{
250 ssize_t res;
251 int off;
252
253 res = vfs_listxattr(ovl_dentry_real(dentry), list, size);
254 if (res <= 0 || size == 0)
255 return res;
256
257 if (ovl_path_type(dentry->d_parent) != OVL_PATH_MERGE)
258 return res;
259
260 /* filter out private xattrs */
261 for (off = 0; off < res;) {
262 char *s = list + off;
263 size_t slen = strlen(s) + 1;
264
265 BUG_ON(off + slen > res);
266
267 if (ovl_is_private_xattr(s)) {
268 res -= slen;
269 memmove(s, s + slen, res - off);
270 } else {
271 off += slen;
272 }
273 }
274
275 return res;
276}
277
278int ovl_removexattr(struct dentry *dentry, const char *name)
279{
280 int err;
281 struct path realpath;
282 enum ovl_path_type type;
283
284 err = ovl_want_write(dentry);
285 if (err)
286 goto out;
287
288 if (ovl_path_type(dentry->d_parent) == OVL_PATH_MERGE &&
289 ovl_is_private_xattr(name))
290 goto out_drop_write;
291
292 type = ovl_path_real(dentry, &realpath);
293 if (type == OVL_PATH_LOWER) {
294 err = vfs_getxattr(realpath.dentry, name, NULL, 0);
295 if (err < 0)
296 goto out_drop_write;
297
298 err = ovl_copy_up(dentry);
299 if (err)
300 goto out_drop_write;
301
302 ovl_path_upper(dentry, &realpath);
303 }
304
305 err = vfs_removexattr(realpath.dentry, name);
306out_drop_write:
307 ovl_drop_write(dentry);
308out:
309 return err;
310}
311
312static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type,
313 struct dentry *realdentry)
314{
315 if (type != OVL_PATH_LOWER)
316 return false;
317
318 if (special_file(realdentry->d_inode->i_mode))
319 return false;
320
321 if (!(OPEN_FMODE(flags) & FMODE_WRITE) && !(flags & O_TRUNC))
322 return false;
323
324 return true;
325}
326
327static int ovl_dentry_open(struct dentry *dentry, struct file *file,
328 const struct cred *cred)
329{
330 int err;
331 struct path realpath;
332 enum ovl_path_type type;
333 bool want_write = false;
334
335 type = ovl_path_real(dentry, &realpath);
336 if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) {
337 want_write = true;
338 err = ovl_want_write(dentry);
339 if (err)
340 goto out;
341
342 if (file->f_flags & O_TRUNC)
343 err = ovl_copy_up_last(dentry, NULL, true);
344 else
345 err = ovl_copy_up(dentry);
346 if (err)
347 goto out_drop_write;
348
349 ovl_path_upper(dentry, &realpath);
350 }
351
352 err = vfs_open(&realpath, file, cred);
353out_drop_write:
354 if (want_write)
355 ovl_drop_write(dentry);
356out:
357 return err;
358}
359
360static const struct inode_operations ovl_file_inode_operations = {
361 .setattr = ovl_setattr,
362 .permission = ovl_permission,
363 .getattr = ovl_getattr,
364 .setxattr = ovl_setxattr,
365 .getxattr = ovl_getxattr,
366 .listxattr = ovl_listxattr,
367 .removexattr = ovl_removexattr,
368 .dentry_open = ovl_dentry_open,
369};
370
371static const struct inode_operations ovl_symlink_inode_operations = {
372 .setattr = ovl_setattr,
373 .follow_link = ovl_follow_link,
374 .put_link = ovl_put_link,
375 .readlink = ovl_readlink,
376 .getattr = ovl_getattr,
377 .setxattr = ovl_setxattr,
378 .getxattr = ovl_getxattr,
379 .listxattr = ovl_listxattr,
380 .removexattr = ovl_removexattr,
381};
382
383struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
384 struct ovl_entry *oe)
385{
386 struct inode *inode;
387
388 inode = new_inode(sb);
389 if (!inode)
390 return NULL;
391
392 mode &= S_IFMT;
393
394 inode->i_ino = get_next_ino();
395 inode->i_mode = mode;
396 inode->i_flags |= S_NOATIME | S_NOCMTIME;
397
398 switch (mode) {
399 case S_IFDIR:
400 inode->i_private = oe;
401 inode->i_op = &ovl_dir_inode_operations;
402 inode->i_fop = &ovl_dir_operations;
403 break;
404
405 case S_IFLNK:
406 inode->i_op = &ovl_symlink_inode_operations;
407 break;
408
409 case S_IFREG:
410 case S_IFSOCK:
411 case S_IFBLK:
412 case S_IFCHR:
413 case S_IFIFO:
414 inode->i_op = &ovl_file_inode_operations;
415 break;
416
417 default:
418 WARN(1, "illegal file type: %i\n", mode);
419 iput(inode);
420 inode = NULL;
421 }
422
423 return inode;
424
425}
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
new file mode 100644
index 000000000000..814bed33dd07
--- /dev/null
+++ b/fs/overlayfs/overlayfs.h
@@ -0,0 +1,191 @@
1/*
2 *
3 * Copyright (C) 2011 Novell Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/kernel.h>
11
12struct ovl_entry;
13
14enum ovl_path_type {
15 OVL_PATH_PURE_UPPER,
16 OVL_PATH_UPPER,
17 OVL_PATH_MERGE,
18 OVL_PATH_LOWER,
19};
20
21extern const char *ovl_opaque_xattr;
22
23static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
24{
25 int err = vfs_rmdir(dir, dentry);
26 pr_debug("rmdir(%pd2) = %i\n", dentry, err);
27 return err;
28}
29
30static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry)
31{
32 int err = vfs_unlink(dir, dentry, NULL);
33 pr_debug("unlink(%pd2) = %i\n", dentry, err);
34 return err;
35}
36
37static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir,
38 struct dentry *new_dentry, bool debug)
39{
40 int err = vfs_link(old_dentry, dir, new_dentry, NULL);
41 if (debug) {
42 pr_debug("link(%pd2, %pd2) = %i\n",
43 old_dentry, new_dentry, err);
44 }
45 return err;
46}
47
48static inline int ovl_do_create(struct inode *dir, struct dentry *dentry,
49 umode_t mode, bool debug)
50{
51 int err = vfs_create(dir, dentry, mode, true);
52 if (debug)
53 pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
54 return err;
55}
56
57static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry,
58 umode_t mode, bool debug)
59{
60 int err = vfs_mkdir(dir, dentry, mode);
61 if (debug)
62 pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
63 return err;
64}
65
66static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry,
67 umode_t mode, dev_t dev, bool debug)
68{
69 int err = vfs_mknod(dir, dentry, mode, dev);
70 if (debug) {
71 pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n",
72 dentry, mode, dev, err);
73 }
74 return err;
75}
76
77static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry,
78 const char *oldname, bool debug)
79{
80 int err = vfs_symlink(dir, dentry, oldname);
81 if (debug)
82 pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
83 return err;
84}
85
86static inline int ovl_do_setxattr(struct dentry *dentry, const char *name,
87 const void *value, size_t size, int flags)
88{
89 int err = vfs_setxattr(dentry, name, value, size, flags);
90 pr_debug("setxattr(%pd2, \"%s\", \"%*s\", 0x%x) = %i\n",
91 dentry, name, (int) size, (char *) value, flags, err);
92 return err;
93}
94
95static inline int ovl_do_removexattr(struct dentry *dentry, const char *name)
96{
97 int err = vfs_removexattr(dentry, name);
98 pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
99 return err;
100}
101
102static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry,
103 struct inode *newdir, struct dentry *newdentry,
104 unsigned int flags)
105{
106 int err;
107
108 pr_debug("rename2(%pd2, %pd2, 0x%x)\n",
109 olddentry, newdentry, flags);
110
111 err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags);
112
113 if (err) {
114 pr_debug("...rename2(%pd2, %pd2, ...) = %i\n",
115 olddentry, newdentry, err);
116 }
117 return err;
118}
119
120static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry)
121{
122 int err = vfs_whiteout(dir, dentry);
123 pr_debug("whiteout(%pd2) = %i\n", dentry, err);
124 return err;
125}
126
127enum ovl_path_type ovl_path_type(struct dentry *dentry);
128u64 ovl_dentry_version_get(struct dentry *dentry);
129void ovl_dentry_version_inc(struct dentry *dentry);
130void ovl_path_upper(struct dentry *dentry, struct path *path);
131void ovl_path_lower(struct dentry *dentry, struct path *path);
132enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
133struct dentry *ovl_dentry_upper(struct dentry *dentry);
134struct dentry *ovl_dentry_lower(struct dentry *dentry);
135struct dentry *ovl_dentry_real(struct dentry *dentry);
136struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper);
137struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
138void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
139struct dentry *ovl_workdir(struct dentry *dentry);
140int ovl_want_write(struct dentry *dentry);
141void ovl_drop_write(struct dentry *dentry);
142bool ovl_dentry_is_opaque(struct dentry *dentry);
143void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque);
144bool ovl_is_whiteout(struct dentry *dentry);
145void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry);
146struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
147 unsigned int flags);
148struct file *ovl_path_open(struct path *path, int flags);
149
150struct dentry *ovl_upper_create(struct dentry *upperdir, struct dentry *dentry,
151 struct kstat *stat, const char *link);
152
153/* readdir.c */
154extern const struct file_operations ovl_dir_operations;
155int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
156void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
157void ovl_cache_free(struct list_head *list);
158
159/* inode.c */
160int ovl_setattr(struct dentry *dentry, struct iattr *attr);
161int ovl_permission(struct inode *inode, int mask);
162int ovl_setxattr(struct dentry *dentry, const char *name,
163 const void *value, size_t size, int flags);
164ssize_t ovl_getxattr(struct dentry *dentry, const char *name,
165 void *value, size_t size);
166ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
167int ovl_removexattr(struct dentry *dentry, const char *name);
168
169struct inode *ovl_new_inode(struct super_block *sb, umode_t mode,
170 struct ovl_entry *oe);
171static inline void ovl_copyattr(struct inode *from, struct inode *to)
172{
173 to->i_uid = from->i_uid;
174 to->i_gid = from->i_gid;
175}
176
177/* dir.c */
178extern const struct inode_operations ovl_dir_inode_operations;
179struct dentry *ovl_lookup_temp(struct dentry *workdir, struct dentry *dentry);
180int ovl_create_real(struct inode *dir, struct dentry *newdentry,
181 struct kstat *stat, const char *link,
182 struct dentry *hardlink, bool debug);
183void ovl_cleanup(struct inode *dir, struct dentry *dentry);
184
185/* copy_up.c */
186int ovl_copy_up(struct dentry *dentry);
187int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
188 struct path *lowerpath, struct kstat *stat,
189 struct iattr *attr);
190int ovl_copy_xattr(struct dentry *old, struct dentry *new);
191int ovl_set_attr(struct dentry *upper, struct kstat *stat);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
new file mode 100644
index 000000000000..910553f37aca
--- /dev/null
+++ b/fs/overlayfs/readdir.c
@@ -0,0 +1,590 @@
1/*
2 *
3 * Copyright (C) 2011 Novell Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/fs.h>
11#include <linux/slab.h>
12#include <linux/namei.h>
13#include <linux/file.h>
14#include <linux/xattr.h>
15#include <linux/rbtree.h>
16#include <linux/security.h>
17#include <linux/cred.h>
18#include "overlayfs.h"
19
20struct ovl_cache_entry {
21 unsigned int len;
22 unsigned int type;
23 u64 ino;
24 bool is_whiteout;
25 struct list_head l_node;
26 struct rb_node node;
27 char name[];
28};
29
30struct ovl_dir_cache {
31 long refcount;
32 u64 version;
33 struct list_head entries;
34};
35
36struct ovl_readdir_data {
37 struct dir_context ctx;
38 bool is_merge;
39 struct rb_root root;
40 struct list_head *list;
41 struct list_head middle;
42 int count;
43 int err;
44};
45
46struct ovl_dir_file {
47 bool is_real;
48 bool is_upper;
49 struct ovl_dir_cache *cache;
50 struct ovl_cache_entry cursor;
51 struct file *realfile;
52 struct file *upperfile;
53};
54
55static struct ovl_cache_entry *ovl_cache_entry_from_node(struct rb_node *n)
56{
57 return container_of(n, struct ovl_cache_entry, node);
58}
59
60static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root,
61 const char *name, int len)
62{
63 struct rb_node *node = root->rb_node;
64 int cmp;
65
66 while (node) {
67 struct ovl_cache_entry *p = ovl_cache_entry_from_node(node);
68
69 cmp = strncmp(name, p->name, len);
70 if (cmp > 0)
71 node = p->node.rb_right;
72 else if (cmp < 0 || len < p->len)
73 node = p->node.rb_left;
74 else
75 return p;
76 }
77
78 return NULL;
79}
80
81static struct ovl_cache_entry *ovl_cache_entry_new(const char *name, int len,
82 u64 ino, unsigned int d_type)
83{
84 struct ovl_cache_entry *p;
85 size_t size = offsetof(struct ovl_cache_entry, name[len + 1]);
86
87 p = kmalloc(size, GFP_KERNEL);
88 if (p) {
89 memcpy(p->name, name, len);
90 p->name[len] = '\0';
91 p->len = len;
92 p->type = d_type;
93 p->ino = ino;
94 p->is_whiteout = false;
95 }
96
97 return p;
98}
99
100static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
101 const char *name, int len, u64 ino,
102 unsigned int d_type)
103{
104 struct rb_node **newp = &rdd->root.rb_node;
105 struct rb_node *parent = NULL;
106 struct ovl_cache_entry *p;
107
108 while (*newp) {
109 int cmp;
110 struct ovl_cache_entry *tmp;
111
112 parent = *newp;
113 tmp = ovl_cache_entry_from_node(*newp);
114 cmp = strncmp(name, tmp->name, len);
115 if (cmp > 0)
116 newp = &tmp->node.rb_right;
117 else if (cmp < 0 || len < tmp->len)
118 newp = &tmp->node.rb_left;
119 else
120 return 0;
121 }
122
123 p = ovl_cache_entry_new(name, len, ino, d_type);
124 if (p == NULL)
125 return -ENOMEM;
126
127 list_add_tail(&p->l_node, rdd->list);
128 rb_link_node(&p->node, parent, newp);
129 rb_insert_color(&p->node, &rdd->root);
130
131 return 0;
132}
133
134static int ovl_fill_lower(struct ovl_readdir_data *rdd,
135 const char *name, int namelen,
136 loff_t offset, u64 ino, unsigned int d_type)
137{
138 struct ovl_cache_entry *p;
139
140 p = ovl_cache_entry_find(&rdd->root, name, namelen);
141 if (p) {
142 list_move_tail(&p->l_node, &rdd->middle);
143 } else {
144 p = ovl_cache_entry_new(name, namelen, ino, d_type);
145 if (p == NULL)
146 rdd->err = -ENOMEM;
147 else
148 list_add_tail(&p->l_node, &rdd->middle);
149 }
150
151 return rdd->err;
152}
153
154void ovl_cache_free(struct list_head *list)
155{
156 struct ovl_cache_entry *p;
157 struct ovl_cache_entry *n;
158
159 list_for_each_entry_safe(p, n, list, l_node)
160 kfree(p);
161
162 INIT_LIST_HEAD(list);
163}
164
165static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry)
166{
167 struct ovl_dir_cache *cache = od->cache;
168
169 list_del(&od->cursor.l_node);
170 WARN_ON(cache->refcount <= 0);
171 cache->refcount--;
172 if (!cache->refcount) {
173 if (ovl_dir_cache(dentry) == cache)
174 ovl_set_dir_cache(dentry, NULL);
175
176 ovl_cache_free(&cache->entries);
177 kfree(cache);
178 }
179}
180
181static int ovl_fill_merge(void *buf, const char *name, int namelen,
182 loff_t offset, u64 ino, unsigned int d_type)
183{
184 struct ovl_readdir_data *rdd = buf;
185
186 rdd->count++;
187 if (!rdd->is_merge)
188 return ovl_cache_entry_add_rb(rdd, name, namelen, ino, d_type);
189 else
190 return ovl_fill_lower(rdd, name, namelen, offset, ino, d_type);
191}
192
193static inline int ovl_dir_read(struct path *realpath,
194 struct ovl_readdir_data *rdd)
195{
196 struct file *realfile;
197 int err;
198
199 realfile = ovl_path_open(realpath, O_RDONLY | O_DIRECTORY);
200 if (IS_ERR(realfile))
201 return PTR_ERR(realfile);
202
203 rdd->ctx.pos = 0;
204 do {
205 rdd->count = 0;
206 rdd->err = 0;
207 err = iterate_dir(realfile, &rdd->ctx);
208 if (err >= 0)
209 err = rdd->err;
210 } while (!err && rdd->count);
211 fput(realfile);
212
213 return err;
214}
215
216static void ovl_dir_reset(struct file *file)
217{
218 struct ovl_dir_file *od = file->private_data;
219 struct ovl_dir_cache *cache = od->cache;
220 struct dentry *dentry = file->f_path.dentry;
221 enum ovl_path_type type = ovl_path_type(dentry);
222
223 if (cache && ovl_dentry_version_get(dentry) != cache->version) {
224 ovl_cache_put(od, dentry);
225 od->cache = NULL;
226 }
227 WARN_ON(!od->is_real && type != OVL_PATH_MERGE);
228 if (od->is_real && type == OVL_PATH_MERGE)
229 od->is_real = false;
230}
231
232static int ovl_dir_mark_whiteouts(struct dentry *dir,
233 struct ovl_readdir_data *rdd)
234{
235 struct ovl_cache_entry *p;
236 struct dentry *dentry;
237 const struct cred *old_cred;
238 struct cred *override_cred;
239
240 override_cred = prepare_creds();
241 if (!override_cred) {
242 ovl_cache_free(rdd->list);
243 return -ENOMEM;
244 }
245
246 /*
247 * CAP_DAC_OVERRIDE for lookup
248 */
249 cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
250 old_cred = override_creds(override_cred);
251
252 mutex_lock(&dir->d_inode->i_mutex);
253 list_for_each_entry(p, rdd->list, l_node) {
254 if (!p->name)
255 continue;
256
257 if (p->type != DT_CHR)
258 continue;
259
260 dentry = lookup_one_len(p->name, dir, p->len);
261 if (IS_ERR(dentry))
262 continue;
263
264 p->is_whiteout = ovl_is_whiteout(dentry);
265 dput(dentry);
266 }
267 mutex_unlock(&dir->d_inode->i_mutex);
268
269 revert_creds(old_cred);
270 put_cred(override_cred);
271
272 return 0;
273}
274
275static inline int ovl_dir_read_merged(struct path *upperpath,
276 struct path *lowerpath,
277 struct list_head *list)
278{
279 int err;
280 struct ovl_readdir_data rdd = {
281 .ctx.actor = ovl_fill_merge,
282 .list = list,
283 .root = RB_ROOT,
284 .is_merge = false,
285 };
286
287 if (upperpath->dentry) {
288 err = ovl_dir_read(upperpath, &rdd);
289 if (err)
290 goto out;
291
292 if (lowerpath->dentry) {
293 err = ovl_dir_mark_whiteouts(upperpath->dentry, &rdd);
294 if (err)
295 goto out;
296 }
297 }
298 if (lowerpath->dentry) {
299 /*
300 * Insert lowerpath entries before upperpath ones, this allows
301 * offsets to be reasonably constant
302 */
303 list_add(&rdd.middle, rdd.list);
304 rdd.is_merge = true;
305 err = ovl_dir_read(lowerpath, &rdd);
306 list_del(&rdd.middle);
307 }
308out:
309 return err;
310
311}
312
313static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos)
314{
315 struct ovl_cache_entry *p;
316 loff_t off = 0;
317
318 list_for_each_entry(p, &od->cache->entries, l_node) {
319 if (!p->name)
320 continue;
321 if (off >= pos)
322 break;
323 off++;
324 }
325 list_move_tail(&od->cursor.l_node, &p->l_node);
326}
327
328static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
329{
330 int res;
331 struct path lowerpath;
332 struct path upperpath;
333 struct ovl_dir_cache *cache;
334
335 cache = ovl_dir_cache(dentry);
336 if (cache && ovl_dentry_version_get(dentry) == cache->version) {
337 cache->refcount++;
338 return cache;
339 }
340 ovl_set_dir_cache(dentry, NULL);
341
342 cache = kzalloc(sizeof(struct ovl_dir_cache), GFP_KERNEL);
343 if (!cache)
344 return ERR_PTR(-ENOMEM);
345
346 cache->refcount = 1;
347 INIT_LIST_HEAD(&cache->entries);
348
349 ovl_path_lower(dentry, &lowerpath);
350 ovl_path_upper(dentry, &upperpath);
351
352 res = ovl_dir_read_merged(&upperpath, &lowerpath, &cache->entries);
353 if (res) {
354 ovl_cache_free(&cache->entries);
355 kfree(cache);
356 return ERR_PTR(res);
357 }
358
359 cache->version = ovl_dentry_version_get(dentry);
360 ovl_set_dir_cache(dentry, cache);
361
362 return cache;
363}
364
365static int ovl_iterate(struct file *file, struct dir_context *ctx)
366{
367 struct ovl_dir_file *od = file->private_data;
368 struct dentry *dentry = file->f_path.dentry;
369
370 if (!ctx->pos)
371 ovl_dir_reset(file);
372
373 if (od->is_real)
374 return iterate_dir(od->realfile, ctx);
375
376 if (!od->cache) {
377 struct ovl_dir_cache *cache;
378
379 cache = ovl_cache_get(dentry);
380 if (IS_ERR(cache))
381 return PTR_ERR(cache);
382
383 od->cache = cache;
384 ovl_seek_cursor(od, ctx->pos);
385 }
386
387 while (od->cursor.l_node.next != &od->cache->entries) {
388 struct ovl_cache_entry *p;
389
390 p = list_entry(od->cursor.l_node.next, struct ovl_cache_entry, l_node);
391 /* Skip cursors */
392 if (p->name) {
393 if (!p->is_whiteout) {
394 if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
395 break;
396 }
397 ctx->pos++;
398 }
399 list_move(&od->cursor.l_node, &p->l_node);
400 }
401 return 0;
402}
403
404static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
405{
406 loff_t res;
407 struct ovl_dir_file *od = file->private_data;
408
409 mutex_lock(&file_inode(file)->i_mutex);
410 if (!file->f_pos)
411 ovl_dir_reset(file);
412
413 if (od->is_real) {
414 res = vfs_llseek(od->realfile, offset, origin);
415 file->f_pos = od->realfile->f_pos;
416 } else {
417 res = -EINVAL;
418
419 switch (origin) {
420 case SEEK_CUR:
421 offset += file->f_pos;
422 break;
423 case SEEK_SET:
424 break;
425 default:
426 goto out_unlock;
427 }
428 if (offset < 0)
429 goto out_unlock;
430
431 if (offset != file->f_pos) {
432 file->f_pos = offset;
433 if (od->cache)
434 ovl_seek_cursor(od, offset);
435 }
436 res = offset;
437 }
438out_unlock:
439 mutex_unlock(&file_inode(file)->i_mutex);
440
441 return res;
442}
443
444static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
445 int datasync)
446{
447 struct ovl_dir_file *od = file->private_data;
448 struct dentry *dentry = file->f_path.dentry;
449 struct file *realfile = od->realfile;
450
451 /*
452 * Need to check if we started out being a lower dir, but got copied up
453 */
454 if (!od->is_upper && ovl_path_type(dentry) == OVL_PATH_MERGE) {
455 struct inode *inode = file_inode(file);
456
457 realfile = od->upperfile;
458 if (!realfile) {
459 struct path upperpath;
460
461 ovl_path_upper(dentry, &upperpath);
462 realfile = ovl_path_open(&upperpath, O_RDONLY);
463 mutex_lock(&inode->i_mutex);
464 if (!od->upperfile) {
465 if (IS_ERR(realfile)) {
466 mutex_unlock(&inode->i_mutex);
467 return PTR_ERR(realfile);
468 }
469 od->upperfile = realfile;
470 } else {
471 /* somebody has beaten us to it */
472 if (!IS_ERR(realfile))
473 fput(realfile);
474 realfile = od->upperfile;
475 }
476 mutex_unlock(&inode->i_mutex);
477 }
478 }
479
480 return vfs_fsync_range(realfile, start, end, datasync);
481}
482
483static int ovl_dir_release(struct inode *inode, struct file *file)
484{
485 struct ovl_dir_file *od = file->private_data;
486
487 if (od->cache) {
488 mutex_lock(&inode->i_mutex);
489 ovl_cache_put(od, file->f_path.dentry);
490 mutex_unlock(&inode->i_mutex);
491 }
492 fput(od->realfile);
493 if (od->upperfile)
494 fput(od->upperfile);
495 kfree(od);
496
497 return 0;
498}
499
500static int ovl_dir_open(struct inode *inode, struct file *file)
501{
502 struct path realpath;
503 struct file *realfile;
504 struct ovl_dir_file *od;
505 enum ovl_path_type type;
506
507 od = kzalloc(sizeof(struct ovl_dir_file), GFP_KERNEL);
508 if (!od)
509 return -ENOMEM;
510
511 type = ovl_path_real(file->f_path.dentry, &realpath);
512 realfile = ovl_path_open(&realpath, file->f_flags);
513 if (IS_ERR(realfile)) {
514 kfree(od);
515 return PTR_ERR(realfile);
516 }
517 INIT_LIST_HEAD(&od->cursor.l_node);
518 od->realfile = realfile;
519 od->is_real = (type != OVL_PATH_MERGE);
520 od->is_upper = (type != OVL_PATH_LOWER);
521 file->private_data = od;
522
523 return 0;
524}
525
526const struct file_operations ovl_dir_operations = {
527 .read = generic_read_dir,
528 .open = ovl_dir_open,
529 .iterate = ovl_iterate,
530 .llseek = ovl_dir_llseek,
531 .fsync = ovl_dir_fsync,
532 .release = ovl_dir_release,
533};
534
535int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
536{
537 int err;
538 struct path lowerpath;
539 struct path upperpath;
540 struct ovl_cache_entry *p;
541
542 ovl_path_upper(dentry, &upperpath);
543 ovl_path_lower(dentry, &lowerpath);
544
545 err = ovl_dir_read_merged(&upperpath, &lowerpath, list);
546 if (err)
547 return err;
548
549 err = 0;
550
551 list_for_each_entry(p, list, l_node) {
552 if (p->is_whiteout)
553 continue;
554
555 if (p->name[0] == '.') {
556 if (p->len == 1)
557 continue;
558 if (p->len == 2 && p->name[1] == '.')
559 continue;
560 }
561 err = -ENOTEMPTY;
562 break;
563 }
564
565 return err;
566}
567
568void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
569{
570 struct ovl_cache_entry *p;
571
572 mutex_lock_nested(&upper->d_inode->i_mutex, I_MUTEX_PARENT);
573 list_for_each_entry(p, list, l_node) {
574 struct dentry *dentry;
575
576 if (!p->is_whiteout)
577 continue;
578
579 dentry = lookup_one_len(p->name, upper, p->len);
580 if (IS_ERR(dentry)) {
581 pr_err("overlayfs: lookup '%s/%.*s' failed (%i)\n",
582 upper->d_name.name, p->len, p->name,
583 (int) PTR_ERR(dentry));
584 continue;
585 }
586 ovl_cleanup(upper->d_inode, dentry);
587 dput(dentry);
588 }
589 mutex_unlock(&upper->d_inode->i_mutex);
590}
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
new file mode 100644
index 000000000000..08b704cebfc4
--- /dev/null
+++ b/fs/overlayfs/super.c
@@ -0,0 +1,796 @@
1/*
2 *
3 * Copyright (C) 2011 Novell Inc.
4 *
5 * This program is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 as published by
7 * the Free Software Foundation.
8 */
9
10#include <linux/fs.h>
11#include <linux/namei.h>
12#include <linux/xattr.h>
13#include <linux/security.h>
14#include <linux/mount.h>
15#include <linux/slab.h>
16#include <linux/parser.h>
17#include <linux/module.h>
18#include <linux/sched.h>
19#include <linux/statfs.h>
20#include <linux/seq_file.h>
21#include "overlayfs.h"
22
23MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>");
24MODULE_DESCRIPTION("Overlay filesystem");
25MODULE_LICENSE("GPL");
26
27#define OVERLAYFS_SUPER_MAGIC 0x794c764f
28
29struct ovl_config {
30 char *lowerdir;
31 char *upperdir;
32 char *workdir;
33};
34
35/* private information held for overlayfs's superblock */
36struct ovl_fs {
37 struct vfsmount *upper_mnt;
38 struct vfsmount *lower_mnt;
39 struct dentry *workdir;
40 long lower_namelen;
41 /* pathnames of lower and upper dirs, for show_options */
42 struct ovl_config config;
43};
44
45struct ovl_dir_cache;
46
47/* private information held for every overlayfs dentry */
48struct ovl_entry {
49 struct dentry *__upperdentry;
50 struct dentry *lowerdentry;
51 struct ovl_dir_cache *cache;
52 union {
53 struct {
54 u64 version;
55 bool opaque;
56 };
57 struct rcu_head rcu;
58 };
59};
60
61const char *ovl_opaque_xattr = "trusted.overlay.opaque";
62
63
64enum ovl_path_type ovl_path_type(struct dentry *dentry)
65{
66 struct ovl_entry *oe = dentry->d_fsdata;
67
68 if (oe->__upperdentry) {
69 if (oe->lowerdentry) {
70 if (S_ISDIR(dentry->d_inode->i_mode))
71 return OVL_PATH_MERGE;
72 else
73 return OVL_PATH_UPPER;
74 } else {
75 if (oe->opaque)
76 return OVL_PATH_UPPER;
77 else
78 return OVL_PATH_PURE_UPPER;
79 }
80 } else {
81 return OVL_PATH_LOWER;
82 }
83}
84
85static struct dentry *ovl_upperdentry_dereference(struct ovl_entry *oe)
86{
87 struct dentry *upperdentry = ACCESS_ONCE(oe->__upperdentry);
88 /*
89 * Make sure to order reads to upperdentry wrt ovl_dentry_update()
90 */
91 smp_read_barrier_depends();
92 return upperdentry;
93}
94
95void ovl_path_upper(struct dentry *dentry, struct path *path)
96{
97 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
98 struct ovl_entry *oe = dentry->d_fsdata;
99
100 path->mnt = ofs->upper_mnt;
101 path->dentry = ovl_upperdentry_dereference(oe);
102}
103
104enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path)
105{
106
107 enum ovl_path_type type = ovl_path_type(dentry);
108
109 if (type == OVL_PATH_LOWER)
110 ovl_path_lower(dentry, path);
111 else
112 ovl_path_upper(dentry, path);
113
114 return type;
115}
116
117struct dentry *ovl_dentry_upper(struct dentry *dentry)
118{
119 struct ovl_entry *oe = dentry->d_fsdata;
120
121 return ovl_upperdentry_dereference(oe);
122}
123
124struct dentry *ovl_dentry_lower(struct dentry *dentry)
125{
126 struct ovl_entry *oe = dentry->d_fsdata;
127
128 return oe->lowerdentry;
129}
130
131struct dentry *ovl_dentry_real(struct dentry *dentry)
132{
133 struct ovl_entry *oe = dentry->d_fsdata;
134 struct dentry *realdentry;
135
136 realdentry = ovl_upperdentry_dereference(oe);
137 if (!realdentry)
138 realdentry = oe->lowerdentry;
139
140 return realdentry;
141}
142
143struct dentry *ovl_entry_real(struct ovl_entry *oe, bool *is_upper)
144{
145 struct dentry *realdentry;
146
147 realdentry = ovl_upperdentry_dereference(oe);
148 if (realdentry) {
149 *is_upper = true;
150 } else {
151 realdentry = oe->lowerdentry;
152 *is_upper = false;
153 }
154 return realdentry;
155}
156
157struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
158{
159 struct ovl_entry *oe = dentry->d_fsdata;
160
161 return oe->cache;
162}
163
164void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
165{
166 struct ovl_entry *oe = dentry->d_fsdata;
167
168 oe->cache = cache;
169}
170
171void ovl_path_lower(struct dentry *dentry, struct path *path)
172{
173 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
174 struct ovl_entry *oe = dentry->d_fsdata;
175
176 path->mnt = ofs->lower_mnt;
177 path->dentry = oe->lowerdentry;
178}
179
180int ovl_want_write(struct dentry *dentry)
181{
182 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
183 return mnt_want_write(ofs->upper_mnt);
184}
185
186void ovl_drop_write(struct dentry *dentry)
187{
188 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
189 mnt_drop_write(ofs->upper_mnt);
190}
191
192struct dentry *ovl_workdir(struct dentry *dentry)
193{
194 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
195 return ofs->workdir;
196}
197
198bool ovl_dentry_is_opaque(struct dentry *dentry)
199{
200 struct ovl_entry *oe = dentry->d_fsdata;
201 return oe->opaque;
202}
203
204void ovl_dentry_set_opaque(struct dentry *dentry, bool opaque)
205{
206 struct ovl_entry *oe = dentry->d_fsdata;
207 oe->opaque = opaque;
208}
209
210void ovl_dentry_update(struct dentry *dentry, struct dentry *upperdentry)
211{
212 struct ovl_entry *oe = dentry->d_fsdata;
213
214 WARN_ON(!mutex_is_locked(&upperdentry->d_parent->d_inode->i_mutex));
215 WARN_ON(oe->__upperdentry);
216 BUG_ON(!upperdentry->d_inode);
217 /*
218 * Make sure upperdentry is consistent before making it visible to
219 * ovl_upperdentry_dereference().
220 */
221 smp_wmb();
222 oe->__upperdentry = upperdentry;
223}
224
225void ovl_dentry_version_inc(struct dentry *dentry)
226{
227 struct ovl_entry *oe = dentry->d_fsdata;
228
229 WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
230 oe->version++;
231}
232
233u64 ovl_dentry_version_get(struct dentry *dentry)
234{
235 struct ovl_entry *oe = dentry->d_fsdata;
236
237 WARN_ON(!mutex_is_locked(&dentry->d_inode->i_mutex));
238 return oe->version;
239}
240
241bool ovl_is_whiteout(struct dentry *dentry)
242{
243 struct inode *inode = dentry->d_inode;
244
245 return inode && IS_WHITEOUT(inode);
246}
247
248static bool ovl_is_opaquedir(struct dentry *dentry)
249{
250 int res;
251 char val;
252 struct inode *inode = dentry->d_inode;
253
254 if (!S_ISDIR(inode->i_mode) || !inode->i_op->getxattr)
255 return false;
256
257 res = inode->i_op->getxattr(dentry, ovl_opaque_xattr, &val, 1);
258 if (res == 1 && val == 'y')
259 return true;
260
261 return false;
262}
263
264static void ovl_dentry_release(struct dentry *dentry)
265{
266 struct ovl_entry *oe = dentry->d_fsdata;
267
268 if (oe) {
269 dput(oe->__upperdentry);
270 dput(oe->lowerdentry);
271 kfree_rcu(oe, rcu);
272 }
273}
274
275static const struct dentry_operations ovl_dentry_operations = {
276 .d_release = ovl_dentry_release,
277};
278
279static struct ovl_entry *ovl_alloc_entry(void)
280{
281 return kzalloc(sizeof(struct ovl_entry), GFP_KERNEL);
282}
283
284static inline struct dentry *ovl_lookup_real(struct dentry *dir,
285 struct qstr *name)
286{
287 struct dentry *dentry;
288
289 mutex_lock(&dir->d_inode->i_mutex);
290 dentry = lookup_one_len(name->name, dir, name->len);
291 mutex_unlock(&dir->d_inode->i_mutex);
292
293 if (IS_ERR(dentry)) {
294 if (PTR_ERR(dentry) == -ENOENT)
295 dentry = NULL;
296 } else if (!dentry->d_inode) {
297 dput(dentry);
298 dentry = NULL;
299 }
300 return dentry;
301}
302
303struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
304 unsigned int flags)
305{
306 struct ovl_entry *oe;
307 struct dentry *upperdir;
308 struct dentry *lowerdir;
309 struct dentry *upperdentry = NULL;
310 struct dentry *lowerdentry = NULL;
311 struct inode *inode = NULL;
312 int err;
313
314 err = -ENOMEM;
315 oe = ovl_alloc_entry();
316 if (!oe)
317 goto out;
318
319 upperdir = ovl_dentry_upper(dentry->d_parent);
320 lowerdir = ovl_dentry_lower(dentry->d_parent);
321
322 if (upperdir) {
323 upperdentry = ovl_lookup_real(upperdir, &dentry->d_name);
324 err = PTR_ERR(upperdentry);
325 if (IS_ERR(upperdentry))
326 goto out_put_dir;
327
328 if (lowerdir && upperdentry) {
329 if (ovl_is_whiteout(upperdentry)) {
330 dput(upperdentry);
331 upperdentry = NULL;
332 oe->opaque = true;
333 } else if (ovl_is_opaquedir(upperdentry)) {
334 oe->opaque = true;
335 }
336 }
337 }
338 if (lowerdir && !oe->opaque) {
339 lowerdentry = ovl_lookup_real(lowerdir, &dentry->d_name);
340 err = PTR_ERR(lowerdentry);
341 if (IS_ERR(lowerdentry))
342 goto out_dput_upper;
343 }
344
345 if (lowerdentry && upperdentry &&
346 (!S_ISDIR(upperdentry->d_inode->i_mode) ||
347 !S_ISDIR(lowerdentry->d_inode->i_mode))) {
348 dput(lowerdentry);
349 lowerdentry = NULL;
350 oe->opaque = true;
351 }
352
353 if (lowerdentry || upperdentry) {
354 struct dentry *realdentry;
355
356 realdentry = upperdentry ? upperdentry : lowerdentry;
357 err = -ENOMEM;
358 inode = ovl_new_inode(dentry->d_sb, realdentry->d_inode->i_mode,
359 oe);
360 if (!inode)
361 goto out_dput;
362 ovl_copyattr(realdentry->d_inode, inode);
363 }
364
365 oe->__upperdentry = upperdentry;
366 oe->lowerdentry = lowerdentry;
367
368 dentry->d_fsdata = oe;
369 d_add(dentry, inode);
370
371 return NULL;
372
373out_dput:
374 dput(lowerdentry);
375out_dput_upper:
376 dput(upperdentry);
377out_put_dir:
378 kfree(oe);
379out:
380 return ERR_PTR(err);
381}
382
383struct file *ovl_path_open(struct path *path, int flags)
384{
385 return dentry_open(path, flags, current_cred());
386}
387
388static void ovl_put_super(struct super_block *sb)
389{
390 struct ovl_fs *ufs = sb->s_fs_info;
391
392 dput(ufs->workdir);
393 mntput(ufs->upper_mnt);
394 mntput(ufs->lower_mnt);
395
396 kfree(ufs->config.lowerdir);
397 kfree(ufs->config.upperdir);
398 kfree(ufs->config.workdir);
399 kfree(ufs);
400}
401
402/**
403 * ovl_statfs
404 * @sb: The overlayfs super block
405 * @buf: The struct kstatfs to fill in with stats
406 *
407 * Get the filesystem statistics. As writes always target the upper layer
408 * filesystem pass the statfs to the same filesystem.
409 */
410static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf)
411{
412 struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
413 struct dentry *root_dentry = dentry->d_sb->s_root;
414 struct path path;
415 int err;
416
417 ovl_path_upper(root_dentry, &path);
418
419 err = vfs_statfs(&path, buf);
420 if (!err) {
421 buf->f_namelen = max(buf->f_namelen, ofs->lower_namelen);
422 buf->f_type = OVERLAYFS_SUPER_MAGIC;
423 }
424
425 return err;
426}
427
428/**
429 * ovl_show_options
430 *
431 * Prints the mount options for a given superblock.
432 * Returns zero; does not fail.
433 */
434static int ovl_show_options(struct seq_file *m, struct dentry *dentry)
435{
436 struct super_block *sb = dentry->d_sb;
437 struct ovl_fs *ufs = sb->s_fs_info;
438
439 seq_printf(m, ",lowerdir=%s", ufs->config.lowerdir);
440 seq_printf(m, ",upperdir=%s", ufs->config.upperdir);
441 seq_printf(m, ",workdir=%s", ufs->config.workdir);
442 return 0;
443}
444
445static const struct super_operations ovl_super_operations = {
446 .put_super = ovl_put_super,
447 .statfs = ovl_statfs,
448 .show_options = ovl_show_options,
449};
450
451enum {
452 OPT_LOWERDIR,
453 OPT_UPPERDIR,
454 OPT_WORKDIR,
455 OPT_ERR,
456};
457
458static const match_table_t ovl_tokens = {
459 {OPT_LOWERDIR, "lowerdir=%s"},
460 {OPT_UPPERDIR, "upperdir=%s"},
461 {OPT_WORKDIR, "workdir=%s"},
462 {OPT_ERR, NULL}
463};
464
465static int ovl_parse_opt(char *opt, struct ovl_config *config)
466{
467 char *p;
468
469 while ((p = strsep(&opt, ",")) != NULL) {
470 int token;
471 substring_t args[MAX_OPT_ARGS];
472
473 if (!*p)
474 continue;
475
476 token = match_token(p, ovl_tokens, args);
477 switch (token) {
478 case OPT_UPPERDIR:
479 kfree(config->upperdir);
480 config->upperdir = match_strdup(&args[0]);
481 if (!config->upperdir)
482 return -ENOMEM;
483 break;
484
485 case OPT_LOWERDIR:
486 kfree(config->lowerdir);
487 config->lowerdir = match_strdup(&args[0]);
488 if (!config->lowerdir)
489 return -ENOMEM;
490 break;
491
492 case OPT_WORKDIR:
493 kfree(config->workdir);
494 config->workdir = match_strdup(&args[0]);
495 if (!config->workdir)
496 return -ENOMEM;
497 break;
498
499 default:
500 return -EINVAL;
501 }
502 }
503 return 0;
504}
505
506#define OVL_WORKDIR_NAME "work"
507
508static struct dentry *ovl_workdir_create(struct vfsmount *mnt,
509 struct dentry *dentry)
510{
511 struct inode *dir = dentry->d_inode;
512 struct dentry *work;
513 int err;
514 bool retried = false;
515
516 err = mnt_want_write(mnt);
517 if (err)
518 return ERR_PTR(err);
519
520 mutex_lock_nested(&dir->i_mutex, I_MUTEX_PARENT);
521retry:
522 work = lookup_one_len(OVL_WORKDIR_NAME, dentry,
523 strlen(OVL_WORKDIR_NAME));
524
525 if (!IS_ERR(work)) {
526 struct kstat stat = {
527 .mode = S_IFDIR | 0,
528 };
529
530 if (work->d_inode) {
531 err = -EEXIST;
532 if (retried)
533 goto out_dput;
534
535 retried = true;
536 ovl_cleanup(dir, work);
537 dput(work);
538 goto retry;
539 }
540
541 err = ovl_create_real(dir, work, &stat, NULL, NULL, true);
542 if (err)
543 goto out_dput;
544 }
545out_unlock:
546 mutex_unlock(&dir->i_mutex);
547 mnt_drop_write(mnt);
548
549 return work;
550
551out_dput:
552 dput(work);
553 work = ERR_PTR(err);
554 goto out_unlock;
555}
556
557static int ovl_mount_dir(const char *name, struct path *path)
558{
559 int err;
560
561 err = kern_path(name, LOOKUP_FOLLOW, path);
562 if (err) {
563 pr_err("overlayfs: failed to resolve '%s': %i\n", name, err);
564 err = -EINVAL;
565 }
566 return err;
567}
568
569static bool ovl_is_allowed_fs_type(struct dentry *root)
570{
571 const struct dentry_operations *dop = root->d_op;
572
573 /*
574 * We don't support:
575 * - automount filesystems
576 * - filesystems with revalidate (FIXME for lower layer)
577 * - filesystems with case insensitive names
578 */
579 if (dop &&
580 (dop->d_manage || dop->d_automount ||
581 dop->d_revalidate || dop->d_weak_revalidate ||
582 dop->d_compare || dop->d_hash)) {
583 return false;
584 }
585 return true;
586}
587
588/* Workdir should not be subdir of upperdir and vice versa */
589static bool ovl_workdir_ok(struct dentry *workdir, struct dentry *upperdir)
590{
591 bool ok = false;
592
593 if (workdir != upperdir) {
594 ok = (lock_rename(workdir, upperdir) == NULL);
595 unlock_rename(workdir, upperdir);
596 }
597 return ok;
598}
599
600static int ovl_fill_super(struct super_block *sb, void *data, int silent)
601{
602 struct path lowerpath;
603 struct path upperpath;
604 struct path workpath;
605 struct inode *root_inode;
606 struct dentry *root_dentry;
607 struct ovl_entry *oe;
608 struct ovl_fs *ufs;
609 struct kstatfs statfs;
610 int err;
611
612 err = -ENOMEM;
613 ufs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL);
614 if (!ufs)
615 goto out;
616
617 err = ovl_parse_opt((char *) data, &ufs->config);
618 if (err)
619 goto out_free_config;
620
621 /* FIXME: workdir is not needed for a R/O mount */
622 err = -EINVAL;
623 if (!ufs->config.upperdir || !ufs->config.lowerdir ||
624 !ufs->config.workdir) {
625 pr_err("overlayfs: missing upperdir or lowerdir or workdir\n");
626 goto out_free_config;
627 }
628
629 err = -ENOMEM;
630 oe = ovl_alloc_entry();
631 if (oe == NULL)
632 goto out_free_config;
633
634 err = ovl_mount_dir(ufs->config.upperdir, &upperpath);
635 if (err)
636 goto out_free_oe;
637
638 err = ovl_mount_dir(ufs->config.lowerdir, &lowerpath);
639 if (err)
640 goto out_put_upperpath;
641
642 err = ovl_mount_dir(ufs->config.workdir, &workpath);
643 if (err)
644 goto out_put_lowerpath;
645
646 err = -EINVAL;
647 if (!S_ISDIR(upperpath.dentry->d_inode->i_mode) ||
648 !S_ISDIR(lowerpath.dentry->d_inode->i_mode) ||
649 !S_ISDIR(workpath.dentry->d_inode->i_mode)) {
650 pr_err("overlayfs: upperdir or lowerdir or workdir not a directory\n");
651 goto out_put_workpath;
652 }
653
654 if (upperpath.mnt != workpath.mnt) {
655 pr_err("overlayfs: workdir and upperdir must reside under the same mount\n");
656 goto out_put_workpath;
657 }
658 if (!ovl_workdir_ok(workpath.dentry, upperpath.dentry)) {
659 pr_err("overlayfs: workdir and upperdir must be separate subtrees\n");
660 goto out_put_workpath;
661 }
662
663 if (!ovl_is_allowed_fs_type(upperpath.dentry)) {
664 pr_err("overlayfs: filesystem of upperdir is not supported\n");
665 goto out_put_workpath;
666 }
667
668 if (!ovl_is_allowed_fs_type(lowerpath.dentry)) {
669 pr_err("overlayfs: filesystem of lowerdir is not supported\n");
670 goto out_put_workpath;
671 }
672
673 err = vfs_statfs(&lowerpath, &statfs);
674 if (err) {
675 pr_err("overlayfs: statfs failed on lowerpath\n");
676 goto out_put_workpath;
677 }
678 ufs->lower_namelen = statfs.f_namelen;
679
680 sb->s_stack_depth = max(upperpath.mnt->mnt_sb->s_stack_depth,
681 lowerpath.mnt->mnt_sb->s_stack_depth) + 1;
682
683 err = -EINVAL;
684 if (sb->s_stack_depth > FILESYSTEM_MAX_STACK_DEPTH) {
685 pr_err("overlayfs: maximum fs stacking depth exceeded\n");
686 goto out_put_workpath;
687 }
688
689 ufs->upper_mnt = clone_private_mount(&upperpath);
690 err = PTR_ERR(ufs->upper_mnt);
691 if (IS_ERR(ufs->upper_mnt)) {
692 pr_err("overlayfs: failed to clone upperpath\n");
693 goto out_put_workpath;
694 }
695
696 ufs->lower_mnt = clone_private_mount(&lowerpath);
697 err = PTR_ERR(ufs->lower_mnt);
698 if (IS_ERR(ufs->lower_mnt)) {
699 pr_err("overlayfs: failed to clone lowerpath\n");
700 goto out_put_upper_mnt;
701 }
702
703 ufs->workdir = ovl_workdir_create(ufs->upper_mnt, workpath.dentry);
704 err = PTR_ERR(ufs->workdir);
705 if (IS_ERR(ufs->workdir)) {
706 pr_err("overlayfs: failed to create directory %s/%s\n",
707 ufs->config.workdir, OVL_WORKDIR_NAME);
708 goto out_put_lower_mnt;
709 }
710
711 /*
712 * Make lower_mnt R/O. That way fchmod/fchown on lower file
713 * will fail instead of modifying lower fs.
714 */
715 ufs->lower_mnt->mnt_flags |= MNT_READONLY;
716
717 /* If the upper fs is r/o, we mark overlayfs r/o too */
718 if (ufs->upper_mnt->mnt_sb->s_flags & MS_RDONLY)
719 sb->s_flags |= MS_RDONLY;
720
721 sb->s_d_op = &ovl_dentry_operations;
722
723 err = -ENOMEM;
724 root_inode = ovl_new_inode(sb, S_IFDIR, oe);
725 if (!root_inode)
726 goto out_put_workdir;
727
728 root_dentry = d_make_root(root_inode);
729 if (!root_dentry)
730 goto out_put_workdir;
731
732 mntput(upperpath.mnt);
733 mntput(lowerpath.mnt);
734 path_put(&workpath);
735
736 oe->__upperdentry = upperpath.dentry;
737 oe->lowerdentry = lowerpath.dentry;
738
739 root_dentry->d_fsdata = oe;
740
741 sb->s_magic = OVERLAYFS_SUPER_MAGIC;
742 sb->s_op = &ovl_super_operations;
743 sb->s_root = root_dentry;
744 sb->s_fs_info = ufs;
745
746 return 0;
747
748out_put_workdir:
749 dput(ufs->workdir);
750out_put_lower_mnt:
751 mntput(ufs->lower_mnt);
752out_put_upper_mnt:
753 mntput(ufs->upper_mnt);
754out_put_workpath:
755 path_put(&workpath);
756out_put_lowerpath:
757 path_put(&lowerpath);
758out_put_upperpath:
759 path_put(&upperpath);
760out_free_oe:
761 kfree(oe);
762out_free_config:
763 kfree(ufs->config.lowerdir);
764 kfree(ufs->config.upperdir);
765 kfree(ufs->config.workdir);
766 kfree(ufs);
767out:
768 return err;
769}
770
771static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags,
772 const char *dev_name, void *raw_data)
773{
774 return mount_nodev(fs_type, flags, raw_data, ovl_fill_super);
775}
776
777static struct file_system_type ovl_fs_type = {
778 .owner = THIS_MODULE,
779 .name = "overlayfs",
780 .mount = ovl_mount,
781 .kill_sb = kill_anon_super,
782};
783MODULE_ALIAS_FS("overlayfs");
784
785static int __init ovl_init(void)
786{
787 return register_filesystem(&ovl_fs_type);
788}
789
790static void __exit ovl_exit(void)
791{
792 unregister_filesystem(&ovl_fs_type);
793}
794
795module_init(ovl_init);
796module_exit(ovl_exit);
diff --git a/fs/splice.c b/fs/splice.c
index f5cb9ba84510..75c6058eabf2 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -1330,6 +1330,7 @@ long do_splice_direct(struct file *in, loff_t *ppos, struct file *out,
1330 1330
1331 return ret; 1331 return ret;
1332} 1332}
1333EXPORT_SYMBOL(do_splice_direct);
1333 1334
1334static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe, 1335static int splice_pipe_to_pipe(struct pipe_inode_info *ipipe,
1335 struct pipe_inode_info *opipe, 1336 struct pipe_inode_info *opipe,
generated by cgit v1.2.2 (git 2.25.0) at 2025-05-31 23:38:01 -0400