diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/autofs4.txt | 12 | ||||
| -rw-r--r-- | Documentation/filesystems/f2fs.txt | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/overlayfs.txt | 34 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.txt | 6 |
4 files changed, 49 insertions, 7 deletions
diff --git a/Documentation/filesystems/autofs4.txt b/Documentation/filesystems/autofs4.txt index 8444dc3d57e8..f10dd590f69f 100644 --- a/Documentation/filesystems/autofs4.txt +++ b/Documentation/filesystems/autofs4.txt @@ -316,7 +316,7 @@ For version 5, the format of the message is: struct autofs_v5_packet { int proto_version; /* Protocol version */ int type; /* Type of packet */ - autofs_wqt_t wait_queue_entry_token; + autofs_wqt_t wait_queue_token; __u32 dev; __u64 ino; __u32 uid; @@ -341,12 +341,12 @@ The pipe will be set to "packet mode" (equivalent to passing `O_DIRECT`) to _pipe2(2)_ so that a read from the pipe will return at most one packet, and any unread portion of a packet will be discarded. -The `wait_queue_entry_token` is a unique number which can identify a +The `wait_queue_token` is a unique number which can identify a particular request to be acknowledged. When a message is sent over the pipe the affected dentry is marked as either "active" or "expiring" and other accesses to it block until the message is acknowledged using one of the ioctls below and the relevant -`wait_queue_entry_token`. +`wait_queue_token`. Communicating with autofs: root directory ioctls ------------------------------------------------ @@ -358,7 +358,7 @@ capability, or must be the automount daemon. The available ioctl commands are: - **AUTOFS_IOC_READY**: a notification has been handled. The argument - to the ioctl command is the "wait_queue_entry_token" number + to the ioctl command is the "wait_queue_token" number corresponding to the notification being acknowledged. - **AUTOFS_IOC_FAIL**: similar to above, but indicates failure with the error code `ENOENT`. @@ -382,14 +382,14 @@ The available ioctl commands are: struct autofs_packet_expire_multi { int proto_version; /* Protocol version */ int type; /* Type of packet */ - autofs_wqt_t wait_queue_entry_token; + autofs_wqt_t wait_queue_token; int len; char name[NAME_MAX+1]; }; is required. This is filled in with the name of something that can be unmounted or removed. If nothing can be expired, - `errno` is set to `EAGAIN`. Even though a `wait_queue_entry_token` + `errno` is set to `EAGAIN`. Even though a `wait_queue_token` is present in the structure, no "wait queue" is established and no acknowledgment is needed. - **AUTOFS_IOC_EXPIRE_MULTI**: This is similar to diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt index 4f6531a4701b..273ccb26885e 100644 --- a/Documentation/filesystems/f2fs.txt +++ b/Documentation/filesystems/f2fs.txt @@ -155,11 +155,15 @@ noinline_data Disable the inline data feature, inline data feature is enabled by default. data_flush Enable data flushing before checkpoint in order to persist data of regular and symlink. +fault_injection=%d Enable fault injection in all supported types with + specified injection rate. mode=%s Control block allocation mode which supports "adaptive" and "lfs". In "lfs" mode, there should be no random writes towards main area. io_bits=%u Set the bit size of write IO requests. It should be set with "mode=lfs". +usrquota Enable plain user disk quota accounting. +grpquota Enable plain group disk quota accounting. ================================================================================ DEBUGFS ENTRIES diff --git a/Documentation/filesystems/overlayfs.txt b/Documentation/filesystems/overlayfs.txt index c9e884b52698..36f528a7fdd6 100644 --- a/Documentation/filesystems/overlayfs.txt +++ b/Documentation/filesystems/overlayfs.txt @@ -201,6 +201,40 @@ rightmost one and going left. In the above example lower1 will be the top, lower2 the middle and lower3 the bottom layer. +Sharing and copying layers +-------------------------- + +Lower layers may be shared among several overlay mounts and that is indeed +a very common practice. An overlay mount may use the same lower layer +path as another overlay mount and it may use a lower layer path that is +beneath or above the path of another overlay lower layer path. + +Using an upper layer path and/or a workdir path that are already used by +another overlay mount is not allowed and will fail with EBUSY. Using +partially overlapping paths is not allowed but will not fail with EBUSY. + +Mounting an overlay using an upper layer path, where the upper layer path +was previously used by another mounted overlay in combination with a +different lower layer path, is allowed, unless the "inodes index" feature +is enabled. + +With the "inodes index" feature, on the first time mount, an NFS file +handle of the lower layer root directory, along with the UUID of the lower +filesystem, are encoded and stored in the "trusted.overlay.origin" extended +attribute on the upper layer root directory. On subsequent mount attempts, +the lower root directory file handle and lower filesystem UUID are compared +to the stored origin in upper root directory. On failure to verify the +lower root origin, mount will fail with ESTALE. An overlayfs mount with +"inodes index" enabled will fail with EOPNOTSUPP if the lower filesystem +does not support NFS export, lower filesystem does not have a valid UUID or +if the upper filesystem does not support extended attributes. + +It is quite a common practice to copy overlay layers to a different +directory tree on the same or different underlying filesystem, and even +to a different machine. With the "inodes index" feature, trying to mount +the copied layers will fail the verification of the lower root file handle. + + Non-standard behavior --------------------- diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index 4cddbce85ac9..adba21b5ada7 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -1786,12 +1786,16 @@ pair provide additional information particular to the objects they represent. pos: 0 flags: 02 mnt_id: 9 - tfd: 5 events: 1d data: ffffffffffffffff + tfd: 5 events: 1d data: ffffffffffffffff pos:0 ino:61af sdev:7 where 'tfd' is a target file descriptor number in decimal form, 'events' is events mask being watched and the 'data' is data associated with a target [see epoll(7) for more details]. + The 'pos' is current offset of the target file in decimal form + [see lseek(2)], 'ino' and 'sdev' are inode and device numbers + where target file resides, all in hex format. + Fsnotify files ~~~~~~~~~~~~~~ For inotify files the format is the following |