Commit 9ca2d732 authored by Richard Weinberger's avatar Richard Weinberger
Browse files

ubifs: Limit number of xattrs per inode 



Since we have to write one deletion inode per xattr
into the journal, limit the max number of xattrs.

In theory UBIFS supported up to 65535 xattrs per inode.
But this never worked correctly, expect no powercuts happened.
Now we support only as many xattrs as we can store in 50% of a
LEB.
Even for tiny flashes this allows dozens of xattrs per inode,
which is for an embedded filesystem still fine.

In case someone has existing inodes with much more xattrs, it is
still possible to delete them.
UBIFS will fall back to an non-atomic deletion mode.

Reported-by: default avatarStefan Agner <stefan@agner.ch>
Fixes: 1e51764a ("UBIFS: add new flash file system")
Signed-off-by: default avatarRichard Weinberger <richard@nod.at>
parent 988bec41

fs/ubifs/dir.c

+14 −1
Original line number Diff line number Diff line
@@ -796,6 +796,10 @@ static int ubifs_unlink(struct inode *dir, struct dentry *dentry) 
	if (err)

		return err;



	err = ubifs_purge_xattrs(inode);

	if (err)

		return err;



	sz_change = CALC_DENT_SIZE(fname_len(&nm));



	ubifs_assert(c, inode_is_locked(dir));
@@ -900,6 +904,10 @@ static int ubifs_rmdir(struct inode *dir, struct dentry *dentry) 
	if (err)

		return err;



	err = ubifs_purge_xattrs(inode);

	if (err)

		return err;



	sz_change = CALC_DENT_SIZE(fname_len(&nm));



	err = ubifs_budget_space(c, &req);
@@ -1282,9 +1290,14 @@ static int do_rename(struct inode *old_dir, struct dentry *old_dentry, 
		old_dentry, old_inode->i_ino, old_dir->i_ino,

		new_dentry, new_dir->i_ino, flags);



	if (unlink)

	if (unlink) {

		ubifs_assert(c, inode_is_locked(new_inode));



		err = ubifs_purge_xattrs(new_inode);

		if (err)

			return err;

	}



	if (unlink && is_dir) {

		err = ubifs_check_dir_empty(new_inode);

		if (err)

fs/ubifs/journal.c

+12 −0
Original line number Diff line number Diff line
@@ -892,6 +892,11 @@ int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode) 
		struct inode *xino;

		struct ubifs_dent_node *xent, *pxent = NULL;



		if (ui->xattr_cnt >= ubifs_xattr_max_cnt(c)) {

			ubifs_err(c, "Cannot delete inode, it has too much xattrs!");

			goto out_release;

		}



		lowest_xent_key(c, &key, inode->i_ino);

		while (1) {

			xent = ubifs_tnc_next_ent(c, &key, &nm);
@@ -907,6 +912,13 @@ int ubifs_jnl_write_inode(struct ubifs_info *c, const struct inode *inode) 
			fname_len(&nm) = le16_to_cpu(xent->nlen);



			xino = ubifs_iget(c->vfs_sb, xent->inum);

			if (IS_ERR(xino)) {

				err = PTR_ERR(xino);

				ubifs_err(c, "dead directory entry '%s', error %d",

					  xent->name, err);

				ubifs_ro_mode(c, err);

				goto out_release;

			}

			ubifs_assert(c, ubifs_inode(xino)->xattr);



			clear_nlink(xino);

fs/ubifs/misc.h

+8 −0
Original line number Diff line number Diff line
@@ -288,6 +288,14 @@ static inline int ubifs_next_log_lnum(const struct ubifs_info *c, int lnum) 
	return lnum;

}



static inline int ubifs_xattr_max_cnt(struct ubifs_info *c)

{

	int max_xattrs = (c->leb_size / 2) / UBIFS_INO_NODE_SZ;



	ubifs_assert(c, max_xattrs < c->max_orphans);

	return max_xattrs;

}



const char *ubifs_assert_action_name(struct ubifs_info *c);



#endif /* __UBIFS_MISC_H__ */

fs/ubifs/super.c

+2 −0
Original line number Diff line number Diff line
@@ -1548,6 +1548,8 @@ static int mount_ubifs(struct ubifs_info *c) 
		c->bud_bytes, c->bud_bytes >> 10, c->bud_bytes >> 20);

	dbg_gen("max. seq. number:    %llu", c->max_sqnum);

	dbg_gen("commit number:       %llu", c->cmt_no);

	dbg_gen("max. xattrs per inode: %d", ubifs_xattr_max_cnt(c));

	dbg_gen("max orphans:           %d", c->max_orphans);



	return 0;

fs/ubifs/ubifs.h

+1 −0
Original line number Diff line number Diff line
@@ -2017,6 +2017,7 @@ int ubifs_xattr_set(struct inode *host, const char *name, const void *value, 
		    size_t size, int flags, bool check_lock);

ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,

			size_t size);

int ubifs_purge_xattrs(struct inode *host);



#ifdef CONFIG_UBIFS_FS_XATTR

void ubifs_evict_xattr_inode(struct ubifs_info *c, ino_t xattr_inum);

CRA Git | Maintained and supported by SUSTech CRA and CCSE