diff options
| -rw-r--r-- | Documentation/filesystems/Locking | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/porting | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 56 | ||||
| -rw-r--r-- | fs/super.c | 67 | ||||
| -rw-r--r-- | include/linux/fs.h | 14 |
5 files changed, 47 insertions, 103 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 4471a416c27..2e994efe12c 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -166,13 +166,11 @@ prototypes: void (*kill_sb) (struct super_block *); locking rules: may block -get_sb yes mount yes kill_sb yes -->get_sb() returns error or 0 with locked superblock attached to the vfsmount -(exclusive on ->s_umount). -->mount() returns ERR_PTR or the root dentry. +->mount() returns ERR_PTR or the root dentry; its superblock should be locked +on return. ->kill_sb() takes a write-locked superblock, does all shutdown work on it, unlocks and drops the reference. diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index dfbcd1b00b0..0c986c9e851 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -394,3 +394,10 @@ file) you must return -EOPNOTSUPP if FALLOC_FL_PUNCH_HOLE is set in mode. Currently you can only have FALLOC_FL_PUNCH_HOLE with FALLOC_FL_KEEP_SIZE set, so the i_size should not change when hole punching, even when puching the end of a file off. + +-- +[mandatory] + ->get_sb() is gone. Switch to use of ->mount(). Typically it's just +a matter of switching from calling get_sb_... to mount_... and changing the +function type. If you were doing it manually, just switch from setting ->mnt_root +to some pointer to returning that pointer. On errors return ERR_PTR(...). diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 94cf97b901d..ef0714aa8e4 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -95,10 +95,11 @@ functions: extern int unregister_filesystem(struct file_system_type *); The passed struct file_system_type describes your filesystem. When a -request is made to mount a device onto a directory in your filespace, -the VFS will call the appropriate get_sb() method for the specific -filesystem. The dentry for the mount point will then be updated to -point to the root inode for the new filesystem. +request is made to mount a filesystem onto a directory in your namespace, +the VFS will call the appropriate mount() method for the specific +filesystem. New vfsmount refering to the tree returned by ->mount() +will be attached to the mountpoint, so that when pathname resolution +reaches the mountpoint it will jump into the root of that vfsmount. You can see all filesystems that are registered to the kernel in the file /proc/filesystems. @@ -107,14 +108,14 @@ file /proc/filesystems. struct file_system_type ----------------------- -This describes the filesystem. As of kernel 2.6.22, the following +This describes the filesystem. As of kernel 2.6.39, the following members are defined: struct file_system_type { const char *name; int fs_flags; - int (*get_sb) (struct file_system_type *, int, - const char *, void *, struct vfsmount *); + struct dentry (*mount) (struct file_system_type *, int, + const char *, void *); void (*kill_sb) (struct super_block *); struct module *owner; struct file_system_type * next; @@ -128,11 +129,11 @@ struct file_system_type { fs_flags: various flags (i.e. FS_REQUIRES_DEV, FS_NO_DCACHE, etc.) - get_sb: the method to call when a new instance of this + mount: the method to call when a new instance of this filesystem should be mounted kill_sb: the method to call when an instance of this filesystem - should be unmounted + should be shut down owner: for internal VFS use: you should initialize this to THIS_MODULE in most cases. @@ -141,7 +142,7 @@ struct file_system_type { s_lock_key, s_umount_key: lockdep-specific -The get_sb() method has the following arguments: +The mount() method has the following arguments: struct file_system_type *fs_type: describes the filesystem, partly initialized by the specific filesystem code @@ -153,32 +154,39 @@ The get_sb() method has the following arguments: void *data: arbitrary mount options, usually comes as an ASCII string (see "Mount Options" section) - struct vfsmount *mnt: a vfs-internal representation of a mount point +The mount() method must return the root dentry of the tree requested by +caller. An active reference to its superblock must be grabbed and the +superblock must be locked. On failure it should return ERR_PTR(error). -The get_sb() method must determine if the block device specified -in the dev_name and fs_type contains a filesystem of the type the method -supports. If it succeeds in opening the named block device, it initializes a -struct super_block descriptor for the filesystem contained by the block device. -On failure it returns an error. +The arguments match those of mount(2) and their interpretation +depends on filesystem type. E.g. for block filesystems, dev_name is +interpreted as block device name, that device is opened and if it +contains a suitable filesystem image the method creates and initializes +struct super_block accordingly, returning its root dentry to caller. + +->mount() may choose to return a subtree of existing filesystem - it +doesn't have to create a new one. The main result from the caller's +point of view is a reference to dentry at the root of (sub)tree to +be attached; creation of new superblock is a common side effect. The most interesting member of the superblock structure that the -get_sb() method fills in is the "s_op" field. This is a pointer to +mount() method fills in is the "s_op" field. This is a pointer to a "struct super_operations" which describes the next level of the filesystem implementation. -Usually, a filesystem uses one of the generic get_sb() implementations -and provides a fill_super() method instead. The generic methods are: +Usually, a filesystem uses one of the generic mount() implementations +and provides a fill_super() callback instead. The generic variants are: - get_sb_bdev: mount a filesystem residing on a block device + mount_bdev: mount a filesystem residing on a block device - get_sb_nodev: mount a filesystem that is not backed by a device + mount_nodev: mount a filesystem that is not backed by a device - get_sb_single: mount a filesystem which shares the instance between + mount_single: mount a filesystem which shares the instance between all mounts -A fill_super() method implementation has the following arguments: +A fill_super() callback implementation has the following arguments: - struct super_block *sb: the superblock structure. The method fill_super() + struct super_block *sb: the superblock structure. The callback must initialize this properly. void *data: arbitrary mount options, usually comes as an ASCII diff --git a/fs/super.c b/fs/super.c index 7e9dd4cc2c0..4bae0ef6110 100644 --- a/fs/super.c +++ b/fs/super.c @@ -843,23 +843,6 @@ error: } EXPORT_SYMBOL(mount_bdev); -int get_sb_bdev(struct file_system_type *fs_type, - int flags, const char *dev_name, void *data, - int (*fill_super)(struct super_block *, void *, int), - struct vfsmount *mnt) -{ - struct dentry *root; - - root = mount_bdev(fs_type, flags, dev_name, data, fill_super); - if (IS_ERR(root)) - return PTR_ERR(root); - mnt->mnt_root = root; - mnt->mnt_sb = root->d_sb; - return 0; -} - -EXPORT_SYMBOL(get_sb_bdev); - void kill_block_super(struct super_block *sb) { struct block_device *bdev = sb->s_bdev; @@ -897,22 +880,6 @@ struct dentry *mount_nodev(struct file_system_type *fs_type, } EXPORT_SYMBOL(mount_nodev); -int get_sb_nodev(struct file_system_type *fs_type, - int flags, void *data, - int (*fill_super)(struct super_block *, void *, int), - struct vfsmount *mnt) -{ - struct dentry *root; - - root = mount_nodev(fs_type, flags, data, fill_super); - if (IS_ERR(root)) - return PTR_ERR(root); - mnt->mnt_root = root; - mnt->mnt_sb = root->d_sb; - return 0; -} -EXPORT_SYMBOL(get_sb_nodev); - static int compare_single(struct super_block *s, void *p) { return 1; @@ -943,22 +910,6 @@ struct dentry *mount_single(struct file_system_type *fs_type, } EXPORT_SYMBOL(mount_single); -int get_sb_single(struct file_system_type *fs_type, - int flags, void *data, - int (*fill_super)(struct super_block *, void *, int), - struct vfsmount *mnt) -{ - struct dentry *root; - root = mount_single(fs_type, flags, data, fill_super); - if (IS_ERR(root)) - return PTR_ERR(root); - mnt->mnt_root = root; - mnt->mnt_sb = root->d_sb; - return 0; -} - -EXPORT_SYMBOL(get_sb_single); - struct vfsmount * vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void *data) { @@ -988,19 +939,13 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void goto out_free_secdata; } - if (type->mount) { - root = type->mount(type, flags, name, data); - if (IS_ERR(root)) { - error = PTR_ERR(root); - goto out_free_secdata; - } - mnt->mnt_root = root; - mnt->mnt_sb = root->d_sb; - } else { - error = type->get_sb(type, flags, name, data, mnt); - if (error < 0) - goto out_free_secdata; + root = type->mount(type, flags, name, data); + if (IS_ERR(root)) { + error = PTR_ERR(root); + goto out_free_secdata; } + mnt->mnt_root = root; + mnt->mnt_sb = root->d_sb; BUG_ON(!mnt->mnt_sb); WARN_ON(!mnt->mnt_sb->s_bdi); mnt->mnt_sb->s_flags |= MS_BORN; diff --git a/include/linux/fs.h b/include/linux/fs.h index e6d3fe45981..ffaa0e4926e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1797,8 +1797,6 @@ int sync_inode_metadata(struct inode *inode, int wait); struct file_system_type { const char *name; int fs_flags; - int (*get_sb) (struct file_system_type *, int, - const char *, void *, struct vfsmount *); struct dentry *(*mount) (struct file_system_type *, int, const char *, void *); void (*kill_sb) (struct super_block *); @@ -1821,24 +1819,12 @@ extern struct dentry *mount_ns(struct file_system_type *fs_type, int flags, extern struct dentry *mount_bdev(struct file_system_type *fs_type, int flags, const char *dev_name, void *data, int (*fill_super)(struct super_block *, void *, int)); -extern int get_sb_bdev(struct file_system_type *fs_type, - int flags, const char *dev_name, void *data, - int (*fill_super)(struct super_block *, void *, int), - struct vfsmount *mnt); extern struct dentry *mount_single(struct file_system_type *fs_type, int flags, void *data, int (*fill_super)(struct super_block *, void *, int)); -extern int get_sb_single(struct file_system_type *fs_type, - int flags, void *data, - int (*fill_super)(struct super_block *, void *, int), - struct vfsmount *mnt); extern struct dentry *mount_nodev(struct file_system_type *fs_type, int flags, void *data, int (*fill_super)(struct super_block *, void *, int)); -extern int get_sb_nodev(struct file_system_type *fs_type, - int flags, void *data, - int (*fill_super)(struct super_block *, void *, int), - struct vfsmount *mnt); void generic_shutdown_super(struct super_block *sb); void kill_block_super(struct super_block *sb); void kill_anon_super(struct super_block *sb); |