diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/isofs.txt | 1 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 50 |
2 files changed, 48 insertions, 3 deletions
diff --git a/Documentation/filesystems/isofs.txt b/Documentation/filesystems/isofs.txt index 758e50401c1..6973b980ca2 100644 --- a/Documentation/filesystems/isofs.txt +++ b/Documentation/filesystems/isofs.txt @@ -24,6 +24,7 @@ Mount options unique to the isofs filesystem. map=normal Map non-Rock Ridge filenames to lower case map=acorn As map=normal but also apply Acorn extensions if present mode=xxx Sets the permissions on files to xxx + dmode=xxx Sets the permissions on directories to xxx nojoliet Ignore Joliet extensions if they are present. norock Ignore Rock Ridge extensions if they are present. hide Completely strip hidden files from the file system. diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index bd55038b56f..81e5be6e6e3 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -151,7 +151,7 @@ The get_sb() method has the following arguments: const char *dev_name: the device name we are mounting. void *data: arbitrary mount options, usually comes as an ASCII - string + string (see "Mount Options" section) struct vfsmount *mnt: a vfs-internal representation of a mount point @@ -182,7 +182,7 @@ A fill_super() method implementation has the following arguments: must initialize this properly. void *data: arbitrary mount options, usually comes as an ASCII - string + string (see "Mount Options" section) int silent: whether or not to be silent on error @@ -291,7 +291,8 @@ or bottom half). umount_begin: called when the VFS is unmounting a filesystem. - show_options: called by the VFS to show mount options for /proc/<pid>/mounts. + show_options: called by the VFS to show mount options for + /proc/<pid>/mounts. (see "Mount Options" section) quota_read: called by the VFS to read from filesystem quota file. @@ -969,6 +970,49 @@ manipulate dentries: For further information on dentry locking, please refer to the document Documentation/filesystems/dentry-locking.txt. +Mount Options +============= + +Parsing options +--------------- + +On mount and remount the filesystem is passed a string containing a +comma separated list of mount options. The options can have either of +these forms: + + option + option=value + +The <linux/parser.h> header defines an API that helps parse these +options. There are plenty of examples on how to use it in existing +filesystems. + +Showing options +--------------- + +If a filesystem accepts mount options, it must define show_options() +to show all the currently active options. The rules are: + + - options MUST be shown which are not default or their values differ + from the default + + - options MAY be shown which are enabled by default or have their + default value + +Options used only internally between a mount helper and the kernel +(such as file descriptors), or which only have an effect during the +mounting (such as ones controlling the creation of a journal) are exempt +from the above rules. + +The underlying reason for the above rules is to make sure, that a +mount can be accurately replicated (e.g. umounting and mounting again) +based on the information found in /proc/mounts. + +A simple method of saving options at mount/remount time and showing +them is provided with the save_mount_options() and +generic_show_options() helper functions. Please note, that using +these may have drawbacks. For more info see header comments for these +functions in fs/namespace.c. Resources ========= |