diff options
Diffstat (limited to 'Documentation/filesystems/vfs.rst')
| -rw-r--r-- | Documentation/filesystems/vfs.rst | 76 |
1 files changed, 17 insertions, 59 deletions
diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst index 670ba66b60e4..7c753148af88 100644 --- a/Documentation/filesystems/vfs.rst +++ b/Documentation/filesystems/vfs.rst @@ -94,11 +94,9 @@ functions: The passed struct file_system_type describes your filesystem. When a 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 referring 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. +namespace, the VFS will call the appropriate get_tree() method for the +specific filesystem. See Documentation/filesystems/mount_api.rst +for more details. You can see all filesystems that are registered to the kernel in the file /proc/filesystems. @@ -117,8 +115,6 @@ members are defined: int fs_flags; int (*init_fs_context)(struct fs_context *); const struct fs_parameter_spec *parameters; - 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; @@ -151,10 +147,6 @@ members are defined: 'struct fs_parameter_spec'. More info in Documentation/filesystems/mount_api.rst. -``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 shut down @@ -173,45 +165,6 @@ members are defined: s_lock_key, s_umount_key, s_vfs_rename_key, s_writers_key, i_lock_key, i_mutex_key, invalidate_lock_key, i_mutex_dir_key: lockdep-specific -The mount() method has the following arguments: - -``struct file_system_type *fs_type`` - describes the filesystem, partly initialized by the specific - filesystem code - -``int flags`` - mount flags - -``const char *dev_name`` - the device name we are mounting. - -``void *data`` - arbitrary mount options, usually comes as an ASCII string (see - "Mount Options" section) - -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 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 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. - -For more information on mounting (and the new mount API), see -Documentation/filesystems/mount_api.rst. - The Superblock Object ===================== @@ -244,7 +197,6 @@ filesystem. The following members are defined: enum freeze_wholder who); int (*unfreeze_fs) (struct super_block *); int (*statfs) (struct dentry *, struct kstatfs *); - int (*remount_fs) (struct super_block *, int *, char *); void (*umount_begin) (struct super_block *); int (*show_options)(struct seq_file *, struct dentry *); @@ -351,10 +303,6 @@ or bottom half). ``statfs`` called when the VFS needs to get filesystem statistics. -``remount_fs`` - called when the filesystem is remounted. This is called with - the kernel lock held - ``umount_begin`` called when the VFS is unmounting a filesystem. @@ -485,7 +433,9 @@ As of kernel 2.6.22, the following members are defined: int (*setattr) (struct mnt_idmap *, struct dentry *, struct iattr *); int (*getattr) (struct mnt_idmap *, const struct path *, struct kstat *, u32, unsigned int); ssize_t (*listxattr) (struct dentry *, char *, size_t); - void (*update_time)(struct inode *, struct timespec *, int); + void (*update_time)(struct inode *inode, enum fs_update_time type, + int flags); + void (*sync_lazytime)(struct inode *inode); int (*atomic_open)(struct inode *, struct dentry *, struct file *, unsigned open_flag, umode_t create_mode); int (*tmpfile) (struct mnt_idmap *, struct inode *, struct file *, umode_t); @@ -642,6 +592,11 @@ otherwise noted. an inode. If this is not defined the VFS will update the inode itself and call mark_inode_dirty_sync. +``sync_lazytime``: + called by the writeback code to update the lazy time stamps to + regular time stamp updates that get syncing into the on-disk + inode. + ``atomic_open`` called on the last component of an open. Using this optional method the filesystem can look up, possibly create and open the @@ -1180,9 +1135,12 @@ otherwise noted. method is used by the splice(2) system call ``setlease`` - called by the VFS to set or release a file lock lease. setlease - implementations should call generic_setlease to record or remove - the lease in the inode after setting it. + called by the VFS to set or release a file lock lease. Local + filesystems that wish to use the kernel-internal lease implementation + should set this to generic_setlease(). Other setlease implementations + should call generic_setlease() to record or remove the lease in the inode + after setting it. When set to NULL, attempts to set or remove a lease will + return -EINVAL. ``fallocate`` called by the VFS to preallocate blocks or punch a hole. |