From 8de52778798fe39660a8d6b26f290e0c93202761 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Mon, 6 Feb 2012 12:45:27 -0500 Subject: vfs: check i_nlink limits in vfs_{mkdir,rename_dir,link} New field of struct super_block - ->s_max_links. Maximal allowed value of ->i_nlink or 0; in the latter case all checks still need to be done in ->link/->mkdir/->rename instances. Note that this limit applies both to directoris and to non-directories. Signed-off-by: Al Viro --- fs/namei.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'fs/namei.c') diff --git a/fs/namei.c b/fs/namei.c index 46ea9cc16647..a0b82762e8fc 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -2569,6 +2569,7 @@ SYSCALL_DEFINE3(mknod, const char __user *, filename, umode_t, mode, unsigned, d int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) { int error = may_create(dir, dentry); + unsigned max_links = dir->i_sb->s_max_links; if (error) return error; @@ -2581,6 +2582,9 @@ int vfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) if (error) return error; + if (max_links && dir->i_nlink >= max_links) + return -EMLINK; + error = dir->i_op->mkdir(dir, dentry, mode); if (!error) fsnotify_mkdir(dir, dentry); @@ -2911,6 +2915,7 @@ SYSCALL_DEFINE2(symlink, const char __user *, oldname, const char __user *, newn int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_dentry) { struct inode *inode = old_dentry->d_inode; + unsigned max_links = dir->i_sb->s_max_links; int error; if (!inode) @@ -2941,6 +2946,8 @@ int vfs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *new_de /* Make sure we don't allow creating hardlink to an unlinked file */ if (inode->i_nlink == 0) error = -ENOENT; + else if (max_links && inode->i_nlink >= max_links) + error = -EMLINK; else error = dir->i_op->link(old_dentry, dir, new_dentry); mutex_unlock(&inode->i_mutex); @@ -3050,6 +3057,7 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, { int error = 0; struct inode *target = new_dentry->d_inode; + unsigned max_links = new_dir->i_sb->s_max_links; /* * If we are going to change the parent - check write permissions, @@ -3073,6 +3081,11 @@ static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry, if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry)) goto out; + error = -EMLINK; + if (max_links && !target && new_dir != old_dir && + new_dir->i_nlink >= max_links) + goto out; + if (target) shrink_dcache_parent(new_dentry); error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); -- cgit v1.2.3 From 68ac1234fb949b66941d94dce4157742799fc581 Mon Sep 17 00:00:00 2001 From: Al Viro Date: Thu, 15 Mar 2012 08:21:57 -0400 Subject: switch touch_atime to struct path Signed-off-by: Al Viro --- fs/cachefiles/namei.c | 3 ++- fs/ecryptfs/file.c | 9 ++++----- fs/inode.c | 5 +++-- fs/namei.c | 2 +- fs/nfsd/vfs.c | 11 ++++++----- fs/stat.c | 2 +- include/linux/fs.h | 4 ++-- net/unix/af_unix.c | 4 ++-- 8 files changed, 21 insertions(+), 19 deletions(-) (limited to 'fs/namei.c') diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index a0358c2189cb..7f0771d3894e 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -646,7 +646,8 @@ lookup_again: * (this is used to keep track of culling, and atimes are only * updated by read, write and readdir but not lookup or * open) */ - touch_atime(cache->mnt, next); + path.dentry = next; + touch_atime(&path); } /* open a file interface onto a data file */ diff --git a/fs/ecryptfs/file.c b/fs/ecryptfs/file.c index d3f95f941c47..2b17f2f9b121 100644 --- a/fs/ecryptfs/file.c +++ b/fs/ecryptfs/file.c @@ -48,8 +48,7 @@ static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb, unsigned long nr_segs, loff_t pos) { ssize_t rc; - struct dentry *lower_dentry; - struct vfsmount *lower_vfsmount; + struct path lower; struct file *file = iocb->ki_filp; rc = generic_file_aio_read(iocb, iov, nr_segs, pos); @@ -60,9 +59,9 @@ static ssize_t ecryptfs_read_update_atime(struct kiocb *iocb, if (-EIOCBQUEUED == rc) rc = wait_on_sync_kiocb(iocb); if (rc >= 0) { - lower_dentry = ecryptfs_dentry_to_lower(file->f_path.dentry); - lower_vfsmount = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry); - touch_atime(lower_vfsmount, lower_dentry); + lower.dentry = ecryptfs_dentry_to_lower(file->f_path.dentry); + lower.mnt = ecryptfs_dentry_to_lower_mnt(file->f_path.dentry); + touch_atime(&lower); } return rc; } diff --git a/fs/inode.c b/fs/inode.c index 92de04b0baa2..8b612813a6a7 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1499,9 +1499,10 @@ static int relatime_need_update(struct vfsmount *mnt, struct inode *inode, * This function automatically handles read only file systems and media, * as well as the "noatime" flag and inode specific "noatime" markers. */ -void touch_atime(struct vfsmount *mnt, struct dentry *dentry) +void touch_atime(struct path *path) { - struct inode *inode = dentry->d_inode; + struct vfsmount *mnt = path->mnt; + struct inode *inode = path->dentry->d_inode; struct timespec now; if (inode->i_flags & S_NOATIME) diff --git a/fs/namei.c b/fs/namei.c index a0b82762e8fc..0ccc74ee92fb 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -642,7 +642,7 @@ follow_link(struct path *link, struct nameidata *nd, void **p) cond_resched(); current->total_link_count++; - touch_atime(link->mnt, dentry); + touch_atime(link); nd_set_link(nd, NULL); error = security_inode_follow_link(link->dentry, nd); diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index edf6d3ed8777..e59f71d0cf73 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1541,30 +1541,31 @@ do_nfsd_create(struct svc_rqst *rqstp, struct svc_fh *fhp, __be32 nfsd_readlink(struct svc_rqst *rqstp, struct svc_fh *fhp, char *buf, int *lenp) { - struct dentry *dentry; struct inode *inode; mm_segment_t oldfs; __be32 err; int host_err; + struct path path; err = fh_verify(rqstp, fhp, S_IFLNK, NFSD_MAY_NOP); if (err) goto out; - dentry = fhp->fh_dentry; - inode = dentry->d_inode; + path.mnt = fhp->fh_export->ex_path.mnt; + path.dentry = fhp->fh_dentry; + inode = path.dentry->d_inode; err = nfserr_inval; if (!inode->i_op->readlink) goto out; - touch_atime(fhp->fh_export->ex_path.mnt, dentry); + touch_atime(&path); /* N.B. Why does this call need a get_fs()?? * Remove the set_fs and watch the fireworks:-) --okir */ oldfs = get_fs(); set_fs(KERNEL_DS); - host_err = inode->i_op->readlink(dentry, buf, *lenp); + host_err = inode->i_op->readlink(path.dentry, buf, *lenp); set_fs(oldfs); if (host_err < 0) diff --git a/fs/stat.c b/fs/stat.c index 8806b8997d2e..86f13563a463 100644 --- a/fs/stat.c +++ b/fs/stat.c @@ -307,7 +307,7 @@ SYSCALL_DEFINE4(readlinkat, int, dfd, const char __user *, pathname, if (inode->i_op->readlink) { error = security_inode_readlink(path.dentry); if (!error) { - touch_atime(path.mnt, path.dentry); + touch_atime(&path); error = inode->i_op->readlink(path.dentry, buf, bufsiz); } diff --git a/include/linux/fs.h b/include/linux/fs.h index b89dc4d60d99..9bbe1a9ac432 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1812,11 +1812,11 @@ static inline void inode_inc_iversion(struct inode *inode) spin_unlock(&inode->i_lock); } -extern void touch_atime(struct vfsmount *mnt, struct dentry *dentry); +extern void touch_atime(struct path *); static inline void file_accessed(struct file *file) { if (!(file->f_flags & O_NOATIME)) - touch_atime(file->f_path.mnt, file->f_path.dentry); + touch_atime(&file->f_path); } int sync_inode(struct inode *inode, struct writeback_control *wbc); diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index ef4b780ef63d..081679444a6e 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -771,7 +771,7 @@ static struct sock *unix_find_other(struct net *net, goto put_fail; if (u->sk_type == type) - touch_atime(path.mnt, path.dentry); + touch_atime(&path); path_put(&path); @@ -787,7 +787,7 @@ static struct sock *unix_find_other(struct net *net, struct dentry *dentry; dentry = unix_sk(u)->path.dentry; if (dentry) - touch_atime(unix_sk(u)->path.mnt, dentry); + touch_atime(&unix_sk(u)->path); } else goto fail; } -- cgit v1.2.3