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| author | Miklos Szeredi <miklos@szeredi.hu> | 2006-06-25 16:48:51 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-06-25 21:01:19 +0400 |
| commit | bafa96541b250a7051e3fbc5de6e8369daf8ffec (patch) | |
| tree | 9b758c424fcda2d263c71f25358bb65a0abc15d4 /Documentation/filesystems | |
| parent | 51eb01e73599efb88c6c20b1c226d20309a75450 (diff) | |
| download | linux-bafa96541b250a7051e3fbc5de6e8369daf8ffec.tar.xz | |
[PATCH] fuse: add control filesystem
Add a control filesystem to fuse, replacing the attributes currently exported
through sysfs. An empty directory '/sys/fs/fuse/connections' is still created
in sysfs, and mounting the control filesystem here provides backward
compatibility.
Advantages of the control filesystem over the previous solution:
- allows the object directory and the attributes to be owned by the
filesystem owner, hence letting unpriviled users abort the
filesystem connection
- does not suffer from module unload race
[akpm@osdl.org: fix this fs for recent dhowells depredations]
[akpm@osdl.org: fix 64-bit printk warnings]
Signed-off-by: Miklos Szeredi <miklos@szeredi.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/fuse.txt | 30 |
1 files changed, 21 insertions, 9 deletions
diff --git a/Documentation/filesystems/fuse.txt b/Documentation/filesystems/fuse.txt index e7747774ceb9..324df27704cc 100644 --- a/Documentation/filesystems/fuse.txt +++ b/Documentation/filesystems/fuse.txt @@ -18,6 +18,14 @@ Non-privileged mount (or user mount): user. NOTE: this is not the same as mounts allowed with the "user" option in /etc/fstab, which is not discussed here. +Filesystem connection: + + A connection between the filesystem daemon and the kernel. The + connection exists until either the daemon dies, or the filesystem is + umounted. Note that detaching (or lazy umounting) the filesystem + does _not_ break the connection, in this case it will exist until + the last reference to the filesystem is released. + Mount owner: The user who does the mounting. @@ -86,16 +94,20 @@ Mount options The default is infinite. Note that the size of read requests is limited anyway to 32 pages (which is 128kbyte on i386). -Sysfs -~~~~~ +Control filesystem +~~~~~~~~~~~~~~~~~~ + +There's a control filesystem for FUSE, which can be mounted by: -FUSE sets up the following hierarchy in sysfs: + mount -t fusectl none /sys/fs/fuse/connections - /sys/fs/fuse/connections/N/ +Mounting it under the '/sys/fs/fuse/connections' directory makes it +backwards compatible with earlier versions. -where N is an increasing number allocated to each new connection. +Under the fuse control filesystem each connection has a directory +named by a unique number. -For each connection the following attributes are defined: +For each connection the following files exist within this directory: 'waiting' @@ -110,7 +122,7 @@ For each connection the following attributes are defined: connection. This means that all waiting requests will be aborted an error returned for all aborted and new requests. -Only a privileged user may read or write these attributes. +Only the owner of the mount may read or write these files. Aborting a filesystem connection ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -139,8 +151,8 @@ the filesystem. There are several ways to do this: - Use forced umount (umount -f). Works in all cases but only if filesystem is still attached (it hasn't been lazy unmounted) - - Abort filesystem through the sysfs interface. Most powerful - method, always works. + - Abort filesystem through the FUSE control filesystem. Most + powerful method, always works. How do non-privileged mounts work? ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ |