From b21996e36c8e3b92a84e972378bde80b43acd890 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 20 Sep 2011 09:14:34 -0400 Subject: locks: break delegations on unlink We need to break delegations on any operation that changes the set of links pointing to an inode. Start with unlink. Such operations also hold the i_mutex on a parent directory. Breaking a delegation may require waiting for a timeout (by default 90 seconds) in the case of a unresponsive NFS client. To avoid blocking all directory operations, we therefore drop locks before waiting for the delegation. The logic then looks like: acquire locks ... test for delegation; if found: take reference on inode release locks wait for delegation break drop reference on inode retry It is possible this could never terminate. (Even if we take precautions to prevent another delegation being acquired on the same inode, we could get a different inode on each retry.) But this seems very unlikely. The initial test for a delegation happens after the lock on the target inode is acquired, but the directory inode may have been acquired further up the call stack. We therefore add a "struct inode **" argument to any intervening functions, which we use to pass the inode back up to the caller in the case it needs a delegation synchronously broken. Cc: David Howells Cc: Tyler Hicks Cc: Dustin Kirkland Acked-by: Jeff Layton Signed-off-by: J. Bruce Fields Signed-off-by: Al Viro --- fs/cachefiles/namei.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/cachefiles') diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index f4a08d7fa2f..31d480c0e04 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -294,7 +294,7 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache, if (ret < 0) { cachefiles_io_error(cache, "Unlink security error"); } else { - ret = vfs_unlink(dir->d_inode, rep); + ret = vfs_unlink(dir->d_inode, rep, NULL); if (preemptive) cachefiles_mark_object_buried(cache, rep); -- cgit v1.2.3-70-g09d2 From 8e6d782cab50884ba94324632700e6233a252f6a Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 20 Sep 2011 16:59:58 -0400 Subject: locks: break delegations on rename Cc: David Howells Acked-by: Jeff Layton Signed-off-by: J. Bruce Fields Signed-off-by: Al Viro --- .../lustre/lustre/include/linux/lustre_compat25.h | 4 +- drivers/staging/lustre/lustre/lvfs/lvfs_linux.c | 2 +- fs/cachefiles/namei.c | 2 +- fs/ecryptfs/inode.c | 3 +- fs/namei.c | 47 ++++++++++++++++++++-- fs/nfsd/vfs.c | 2 +- include/linux/fs.h | 2 +- 7 files changed, 51 insertions(+), 11 deletions(-) (limited to 'fs/cachefiles') diff --git a/drivers/staging/lustre/lustre/include/linux/lustre_compat25.h b/drivers/staging/lustre/lustre/include/linux/lustre_compat25.h index 9243dfab43d..80b019bf969 100644 --- a/drivers/staging/lustre/lustre/include/linux/lustre_compat25.h +++ b/drivers/staging/lustre/lustre/include/linux/lustre_compat25.h @@ -105,8 +105,8 @@ static inline void ll_set_fs_pwd(struct fs_struct *fs, struct vfsmount *mnt, #define ll_vfs_unlink(inode,entry,mnt) vfs_unlink(inode,entry) #define ll_vfs_mknod(dir,entry,mnt,mode,dev) vfs_mknod(dir,entry,mode,dev) #define ll_security_inode_unlink(dir,entry,mnt) security_inode_unlink(dir,entry) -#define ll_vfs_rename(old,old_dir,mnt,new,new_dir,mnt1) \ - vfs_rename(old,old_dir,new,new_dir) +#define ll_vfs_rename(old,old_dir,mnt,new,new_dir,mnt1,delegated_inode) \ + vfs_rename(old,old_dir,new,new_dir,delegated_inode) #define cfs_bio_io_error(a,b) bio_io_error((a)) #define cfs_bio_endio(a,b,c) bio_endio((a),(c)) diff --git a/drivers/staging/lustre/lustre/lvfs/lvfs_linux.c b/drivers/staging/lustre/lustre/lvfs/lvfs_linux.c index 18e1b47a1d6..4ed7c9f0a8b 100644 --- a/drivers/staging/lustre/lustre/lvfs/lvfs_linux.c +++ b/drivers/staging/lustre/lustre/lvfs/lvfs_linux.c @@ -220,7 +220,7 @@ int lustre_rename(struct dentry *dir, struct vfsmount *mnt, GOTO(put_old, err = PTR_ERR(dchild_new)); err = ll_vfs_rename(dir->d_inode, dchild_old, mnt, - dir->d_inode, dchild_new, mnt); + dir->d_inode, dchild_new, mnt, NULL); dput(dchild_new); put_old: diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c index 31d480c0e04..ca65f39dc8d 100644 --- a/fs/cachefiles/namei.c +++ b/fs/cachefiles/namei.c @@ -396,7 +396,7 @@ try_again: cachefiles_io_error(cache, "Rename security error %d", ret); } else { ret = vfs_rename(dir->d_inode, rep, - cache->graveyard->d_inode, grave); + cache->graveyard->d_inode, grave, NULL); if (ret != 0 && ret != -ENOMEM) cachefiles_io_error(cache, "Rename failed with error %d", ret); diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index dc60b8bd09e..c23b01bb7e0 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -640,7 +640,8 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry, goto out_lock; } rc = vfs_rename(lower_old_dir_dentry->d_inode, lower_old_dentry, - lower_new_dir_dentry->d_inode, lower_new_dentry); + lower_new_dir_dentry->d_inode, lower_new_dentry, + NULL); if (rc) goto out_lock; if (target_inode) diff --git a/fs/namei.c b/fs/namei.c index cfaeaae0f2d..ce7e580e4e1 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -4022,7 +4022,8 @@ out: } static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry) + struct inode *new_dir, struct dentry *new_dentry, + struct inode **delegated_inode) { struct inode *target = new_dentry->d_inode; struct inode *source = old_dentry->d_inode; @@ -4039,6 +4040,14 @@ static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry, if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry)) goto out; + error = try_break_deleg(source, delegated_inode); + if (error) + goto out; + if (target) { + error = try_break_deleg(target, delegated_inode); + if (error) + goto out; + } error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry); if (error) goto out; @@ -4053,8 +4062,30 @@ out: return error; } +/** + * vfs_rename - rename a filesystem object + * @old_dir: parent of source + * @old_dentry: source + * @new_dir: parent of destination + * @new_dentry: destination + * @delegated_inode: returns an inode needing a delegation break + * + * The caller must hold multiple mutexes--see lock_rename()). + * + * If vfs_rename discovers a delegation in need of breaking at either + * the source or destination, it will return -EWOULDBLOCK and return a + * reference to the inode in delegated_inode. The caller should then + * break the delegation and retry. Because breaking a delegation may + * take a long time, the caller should drop all locks before doing + * so. + * + * Alternatively, a caller may pass NULL for delegated_inode. This may + * be appropriate for callers that expect the underlying filesystem not + * to be NFS exported. + */ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, - struct inode *new_dir, struct dentry *new_dentry) + struct inode *new_dir, struct dentry *new_dentry, + struct inode **delegated_inode) { int error; int is_dir = d_is_directory(old_dentry) || d_is_autodir(old_dentry); @@ -4082,7 +4113,7 @@ int vfs_rename(struct inode *old_dir, struct dentry *old_dentry, if (is_dir) error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry); else - error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry); + error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry,delegated_inode); if (!error) fsnotify_move(old_dir, new_dir, old_name, is_dir, new_dentry->d_inode, old_dentry); @@ -4098,6 +4129,7 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname, struct dentry *old_dentry, *new_dentry; struct dentry *trap; struct nameidata oldnd, newnd; + struct inode *delegated_inode = NULL; struct filename *from; struct filename *to; unsigned int lookup_flags = 0; @@ -4137,6 +4169,7 @@ retry: newnd.flags &= ~LOOKUP_PARENT; newnd.flags |= LOOKUP_RENAME_TARGET; +retry_deleg: trap = lock_rename(new_dir, old_dir); old_dentry = lookup_hash(&oldnd); @@ -4173,13 +4206,19 @@ retry: if (error) goto exit5; error = vfs_rename(old_dir->d_inode, old_dentry, - new_dir->d_inode, new_dentry); + new_dir->d_inode, new_dentry, + &delegated_inode); exit5: dput(new_dentry); exit4: dput(old_dentry); exit3: unlock_rename(new_dir, old_dir); + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } mnt_drop_write(oldnd.path.mnt); exit2: if (retry_estale(error, lookup_flags)) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 7a810235d59..45bf0295894 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -1837,7 +1837,7 @@ nfsd_rename(struct svc_rqst *rqstp, struct svc_fh *ffhp, char *fname, int flen, if (host_err) goto out_dput_new; } - host_err = vfs_rename(fdir, odentry, tdir, ndentry); + host_err = vfs_rename(fdir, odentry, tdir, ndentry, NULL); if (!host_err) { host_err = commit_metadata(tfhp); if (!host_err) diff --git a/include/linux/fs.h b/include/linux/fs.h index 931f919f44e..5bcff883fa9 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1456,7 +1456,7 @@ extern int vfs_symlink(struct inode *, struct dentry *, const char *); extern int vfs_link(struct dentry *, struct inode *, struct dentry *); extern int vfs_rmdir(struct inode *, struct dentry *); extern int vfs_unlink(struct inode *, struct dentry *, struct inode **); -extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *); +extern int vfs_rename(struct inode *, struct dentry *, struct inode *, struct dentry *, struct inode **); /* * VFS dentry helper functions. -- cgit v1.2.3-70-g09d2 From 27ac0ffeac80ba6b9580529568d06144df044366 Mon Sep 17 00:00:00 2001 From: "J. Bruce Fields" Date: Tue, 20 Sep 2011 17:19:26 -0400 Subject: locks: break delegations on any attribute modification NFSv4 uses leases to guarantee that clients can cache metadata as well as data. Cc: Mikulas Patocka Cc: David Howells Cc: Tyler Hicks Cc: Dustin Kirkland Acked-by: Jeff Layton Signed-off-by: J. Bruce Fields Signed-off-by: Al Viro --- drivers/base/devtmpfs.c | 4 ++-- fs/attr.c | 25 ++++++++++++++++++++++++- fs/cachefiles/interface.c | 4 ++-- fs/ecryptfs/inode.c | 4 ++-- fs/hpfs/namei.c | 2 +- fs/inode.c | 6 +++++- fs/nfsd/vfs.c | 8 ++++++-- fs/open.c | 22 ++++++++++++++++++---- fs/utimes.c | 9 ++++++++- include/linux/fs.h | 2 +- 10 files changed, 69 insertions(+), 17 deletions(-) (limited to 'fs/cachefiles') diff --git a/drivers/base/devtmpfs.c b/drivers/base/devtmpfs.c index 1b8490e2fbd..0f3820121e0 100644 --- a/drivers/base/devtmpfs.c +++ b/drivers/base/devtmpfs.c @@ -216,7 +216,7 @@ static int handle_create(const char *nodename, umode_t mode, kuid_t uid, newattrs.ia_gid = gid; newattrs.ia_valid = ATTR_MODE|ATTR_UID|ATTR_GID; mutex_lock(&dentry->d_inode->i_mutex); - notify_change(dentry, &newattrs); + notify_change(dentry, &newattrs, NULL); mutex_unlock(&dentry->d_inode->i_mutex); /* mark as kernel-created inode */ @@ -322,7 +322,7 @@ static int handle_remove(const char *nodename, struct device *dev) newattrs.ia_valid = ATTR_UID|ATTR_GID|ATTR_MODE; mutex_lock(&dentry->d_inode->i_mutex); - notify_change(dentry, &newattrs); + notify_change(dentry, &newattrs, NULL); mutex_unlock(&dentry->d_inode->i_mutex); err = vfs_unlink(parent.dentry->d_inode, dentry, NULL); if (!err || err == -ENOENT) diff --git a/fs/attr.c b/fs/attr.c index 1449adb14ef..267968d9467 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -167,7 +167,27 @@ void setattr_copy(struct inode *inode, const struct iattr *attr) } EXPORT_SYMBOL(setattr_copy); -int notify_change(struct dentry * dentry, struct iattr * attr) +/** + * notify_change - modify attributes of a filesytem object + * @dentry: object affected + * @iattr: new attributes + * @delegated_inode: returns inode, if the inode is delegated + * + * The caller must hold the i_mutex on the affected object. + * + * If notify_change discovers a delegation in need of breaking, + * it will return -EWOULDBLOCK and return a reference to the inode in + * delegated_inode. The caller should then break the delegation and + * retry. Because breaking a delegation may take a long time, the + * caller should drop the i_mutex before doing so. + * + * Alternatively, a caller may pass NULL for delegated_inode. This may + * be appropriate for callers that expect the underlying filesystem not + * to be NFS exported. Also, passing NULL is fine for callers holding + * the file open for write, as there can be no conflicting delegation in + * that case. + */ +int notify_change(struct dentry * dentry, struct iattr * attr, struct inode **delegated_inode) { struct inode *inode = dentry->d_inode; umode_t mode = inode->i_mode; @@ -241,6 +261,9 @@ int notify_change(struct dentry * dentry, struct iattr * attr) return 0; error = security_inode_setattr(dentry, attr); + if (error) + return error; + error = try_break_deleg(inode, delegated_inode); if (error) return error; diff --git a/fs/cachefiles/interface.c b/fs/cachefiles/interface.c index 43eb5592cde..5088a418ac4 100644 --- a/fs/cachefiles/interface.c +++ b/fs/cachefiles/interface.c @@ -449,14 +449,14 @@ static int cachefiles_attr_changed(struct fscache_object *_object) _debug("discard tail %llx", oi_size); newattrs.ia_valid = ATTR_SIZE; newattrs.ia_size = oi_size & PAGE_MASK; - ret = notify_change(object->backer, &newattrs); + ret = notify_change(object->backer, &newattrs, NULL); if (ret < 0) goto truncate_failed; } newattrs.ia_valid = ATTR_SIZE; newattrs.ia_size = ni_size; - ret = notify_change(object->backer, &newattrs); + ret = notify_change(object->backer, &newattrs, NULL); truncate_failed: mutex_unlock(&object->backer->d_inode->i_mutex); diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c index 1c628f02304..c36c4482447 100644 --- a/fs/ecryptfs/inode.c +++ b/fs/ecryptfs/inode.c @@ -882,7 +882,7 @@ int ecryptfs_truncate(struct dentry *dentry, loff_t new_length) struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry); mutex_lock(&lower_dentry->d_inode->i_mutex); - rc = notify_change(lower_dentry, &lower_ia); + rc = notify_change(lower_dentry, &lower_ia, NULL); mutex_unlock(&lower_dentry->d_inode->i_mutex); } return rc; @@ -983,7 +983,7 @@ static int ecryptfs_setattr(struct dentry *dentry, struct iattr *ia) lower_ia.ia_valid &= ~ATTR_MODE; mutex_lock(&lower_dentry->d_inode->i_mutex); - rc = notify_change(lower_dentry, &lower_ia); + rc = notify_change(lower_dentry, &lower_ia, NULL); mutex_unlock(&lower_dentry->d_inode->i_mutex); out: fsstack_copy_attr_all(inode, lower_inode); diff --git a/fs/hpfs/namei.c b/fs/hpfs/namei.c index 345713d2f8f..1b39afdd86f 100644 --- a/fs/hpfs/namei.c +++ b/fs/hpfs/namei.c @@ -407,7 +407,7 @@ again: /*printk("HPFS: truncating file before delete.\n");*/ newattrs.ia_size = 0; newattrs.ia_valid = ATTR_SIZE | ATTR_CTIME; - err = notify_change(dentry, &newattrs); + err = notify_change(dentry, &newattrs, NULL); put_write_access(inode); if (!err) goto again; diff --git a/fs/inode.c b/fs/inode.c index ce48c359ce9..4bcdad3c936 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -1603,7 +1603,11 @@ static int __remove_suid(struct dentry *dentry, int kill) struct iattr newattrs; newattrs.ia_valid = ATTR_FORCE | kill; - return notify_change(dentry, &newattrs); + /* + * Note we call this on write, so notify_change will not + * encounter any conflicting delegations: + */ + return notify_change(dentry, &newattrs, NULL); } int file_remove_suid(struct file *file) diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c index 27ba21b5f38..94b5f5d2bfe 100644 --- a/fs/nfsd/vfs.c +++ b/fs/nfsd/vfs.c @@ -427,7 +427,7 @@ nfsd_setattr(struct svc_rqst *rqstp, struct svc_fh *fhp, struct iattr *iap, goto out_nfserr; fh_lock(fhp); - host_err = notify_change(dentry, iap); + host_err = notify_change(dentry, iap, NULL); err = nfserrno(host_err); fh_unlock(fhp); } @@ -988,7 +988,11 @@ static void kill_suid(struct dentry *dentry) ia.ia_valid = ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; mutex_lock(&dentry->d_inode->i_mutex); - notify_change(dentry, &ia); + /* + * Note we call this on write, so notify_change will not + * encounter any conflicting delegations: + */ + notify_change(dentry, &ia, NULL); mutex_unlock(&dentry->d_inode->i_mutex); } diff --git a/fs/open.c b/fs/open.c index fffbed40dbe..4b3e1edf2fe 100644 --- a/fs/open.c +++ b/fs/open.c @@ -57,7 +57,8 @@ int do_truncate(struct dentry *dentry, loff_t length, unsigned int time_attrs, newattrs.ia_valid |= ret | ATTR_FORCE; mutex_lock(&dentry->d_inode->i_mutex); - ret = notify_change(dentry, &newattrs); + /* Note any delegations or leases have already been broken: */ + ret = notify_change(dentry, &newattrs, NULL); mutex_unlock(&dentry->d_inode->i_mutex); return ret; } @@ -464,21 +465,28 @@ out: static int chmod_common(struct path *path, umode_t mode) { struct inode *inode = path->dentry->d_inode; + struct inode *delegated_inode = NULL; struct iattr newattrs; int error; error = mnt_want_write(path->mnt); if (error) return error; +retry_deleg: mutex_lock(&inode->i_mutex); error = security_path_chmod(path, mode); if (error) goto out_unlock; newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO); newattrs.ia_valid = ATTR_MODE | ATTR_CTIME; - error = notify_change(path->dentry, &newattrs); + error = notify_change(path->dentry, &newattrs, &delegated_inode); out_unlock: mutex_unlock(&inode->i_mutex); + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } mnt_drop_write(path->mnt); return error; } @@ -522,6 +530,7 @@ SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode) static int chown_common(struct path *path, uid_t user, gid_t group) { struct inode *inode = path->dentry->d_inode; + struct inode *delegated_inode = NULL; int error; struct iattr newattrs; kuid_t uid; @@ -546,12 +555,17 @@ static int chown_common(struct path *path, uid_t user, gid_t group) if (!S_ISDIR(inode->i_mode)) newattrs.ia_valid |= ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV; +retry_deleg: mutex_lock(&inode->i_mutex); error = security_path_chown(path, uid, gid); if (!error) - error = notify_change(path->dentry, &newattrs); + error = notify_change(path->dentry, &newattrs, &delegated_inode); mutex_unlock(&inode->i_mutex); - + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } return error; } diff --git a/fs/utimes.c b/fs/utimes.c index f4fb7eca10e..aa138d64560 100644 --- a/fs/utimes.c +++ b/fs/utimes.c @@ -53,6 +53,7 @@ static int utimes_common(struct path *path, struct timespec *times) int error; struct iattr newattrs; struct inode *inode = path->dentry->d_inode; + struct inode *delegated_inode = NULL; error = mnt_want_write(path->mnt); if (error) @@ -101,9 +102,15 @@ static int utimes_common(struct path *path, struct timespec *times) goto mnt_drop_write_and_out; } } +retry_deleg: mutex_lock(&inode->i_mutex); - error = notify_change(path->dentry, &newattrs); + error = notify_change(path->dentry, &newattrs, &delegated_inode); mutex_unlock(&inode->i_mutex); + if (delegated_inode) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } mnt_drop_write_and_out: mnt_drop_write(path->mnt); diff --git a/include/linux/fs.h b/include/linux/fs.h index 6e36e7118ec..ab2a0ca82dc 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -2278,7 +2278,7 @@ extern void emergency_remount(void); #ifdef CONFIG_BLOCK extern sector_t bmap(struct inode *, sector_t); #endif -extern int notify_change(struct dentry *, struct iattr *); +extern int notify_change(struct dentry *, struct iattr *, struct inode **); extern int inode_permission(struct inode *, int); extern int generic_permission(struct inode *, int); -- cgit v1.2.3-70-g09d2