diff options
| -rw-r--r-- | Documentation/filesystems/Locking | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 7 | ||||
| -rw-r--r-- | fs/autofs4/root.c | 8 | ||||
| -rw-r--r-- | fs/namei.c | 15 | ||||
| -rw-r--r-- | include/linux/dcache.h | 2 |
5 files changed, 22 insertions, 12 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index cbf98b989b1..39707748ed2 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -32,7 +32,7 @@ d_release: no no yes no d_iput: no no yes no d_dname: no no no no d_automount: no no yes no -d_manage: no no yes no +d_manage: no no yes (ref-walk) maybe --------------------------- inode_operations --------------------------- prototypes: diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 4682586b147..3c4b2f1b64d 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -865,7 +865,7 @@ struct dentry_operations { void (*d_iput)(struct dentry *, struct inode *); char *(*d_dname)(struct dentry *, char *, int); struct vfsmount *(*d_automount)(struct path *); - int (*d_manage)(struct dentry *, bool); + int (*d_manage)(struct dentry *, bool, bool); }; d_revalidate: called when the VFS needs to revalidate a dentry. This @@ -960,6 +960,11 @@ struct dentry_operations { held by the caller and the function should not initiate any mounts or unmounts that it will then wait for. + If the 'rcu_walk' parameter is true, then the caller is doing a + pathwalk in RCU-walk mode. Sleeping is not permitted in this mode, + and the caller can be asked to leave it and call again by returing + -ECHILD. + This function is only used if DCACHE_MANAGE_TRANSIT is set on the dentry being transited from. diff --git a/fs/autofs4/root.c b/fs/autofs4/root.c index 9194e274f84..dbd95512808 100644 --- a/fs/autofs4/root.c +++ b/fs/autofs4/root.c @@ -36,7 +36,7 @@ static long autofs4_root_compat_ioctl(struct file *,unsigned int,unsigned long); static int autofs4_dir_open(struct inode *inode, struct file *file); static struct dentry *autofs4_lookup(struct inode *,struct dentry *, struct nameidata *); static struct vfsmount *autofs4_d_automount(struct path *); -static int autofs4_d_manage(struct dentry *, bool); +static int autofs4_d_manage(struct dentry *, bool, bool); const struct file_operations autofs4_root_operations = { .open = dcache_dir_open, @@ -450,7 +450,7 @@ done: return NULL; } -int autofs4_d_manage(struct dentry *dentry, bool mounting_here) +int autofs4_d_manage(struct dentry *dentry, bool mounting_here, bool rcu_walk) { struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb); @@ -464,6 +464,10 @@ int autofs4_d_manage(struct dentry *dentry, bool mounting_here) return 0; } + /* We need to sleep, so we need pathwalk to be in ref-mode */ + if (rcu_walk) + return -ECHILD; + /* Wait for pending expires */ do_expire_wait(dentry); diff --git a/fs/namei.c b/fs/namei.c index 37385201271..5c89695ae1e 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -987,7 +987,8 @@ static int follow_managed(struct path *path, unsigned flags) if (managed & DCACHE_MANAGE_TRANSIT) { BUG_ON(!path->dentry->d_op); BUG_ON(!path->dentry->d_op->d_manage); - ret = path->dentry->d_op->d_manage(path->dentry, false); + ret = path->dentry->d_op->d_manage(path->dentry, + false, false); if (ret < 0) return ret == -EISDIR ? 0 : ret; } @@ -1048,13 +1049,12 @@ int follow_down_one(struct path *path) static bool __follow_mount_rcu(struct nameidata *nd, struct path *path, struct inode **inode, bool reverse_transit) { - unsigned abort_mask = - reverse_transit ? 0 : DCACHE_MANAGE_TRANSIT; - while (d_mountpoint(path->dentry)) { struct vfsmount *mounted; - if (path->dentry->d_flags & abort_mask) - return true; + if (unlikely(path->dentry->d_flags & DCACHE_MANAGE_TRANSIT) && + !reverse_transit && + path->dentry->d_op->d_manage(path->dentry, false, true) < 0) + return false; mounted = __lookup_mnt(path->mnt, path->dentry, 1); if (!mounted) break; @@ -1132,7 +1132,8 @@ int follow_down(struct path *path, bool mounting_here) if (managed & DCACHE_MANAGE_TRANSIT) { BUG_ON(!path->dentry->d_op); BUG_ON(!path->dentry->d_op->d_manage); - ret = path->dentry->d_op->d_manage(path->dentry, mounting_here); + ret = path->dentry->d_op->d_manage( + path->dentry, mounting_here, false); if (ret < 0) return ret == -EISDIR ? 0 : ret; } diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 1a87760d653..f958c19e3ca 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -168,7 +168,7 @@ struct dentry_operations { void (*d_iput)(struct dentry *, struct inode *); char *(*d_dname)(struct dentry *, char *, int); struct vfsmount *(*d_automount)(struct path *); - int (*d_manage)(struct dentry *, bool); + int (*d_manage)(struct dentry *, bool, bool); } ____cacheline_aligned; /* |