diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/Locking | 24 | ||||
| -rw-r--r-- | Documentation/filesystems/caching/cachefiles.txt | 8 | ||||
| -rw-r--r-- | Documentation/filesystems/gfs2-glocks.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/gfs2.txt | 19 | ||||
| -rw-r--r-- | Documentation/filesystems/tmpfs.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 3 |
6 files changed, 34 insertions, 24 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 76efe5b71d7d..3120f8dd2c31 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -512,16 +512,24 @@ locking rules: BKL mmap_sem PageLocked(page) open: no yes close: no yes -fault: no yes -page_mkwrite: no yes no +fault: no yes can return with page locked +page_mkwrite: no yes can return with page locked access: no yes - ->page_mkwrite() is called when a previously read-only page is -about to become writeable. The file system is responsible for -protecting against truncate races. Once appropriate action has been -taking to lock out truncate, the page range should be verified to be -within i_size. The page mapping should also be checked that it is not -NULL. + ->fault() is called when a previously not present pte is about +to be faulted in. The filesystem must find and return the page associated +with the passed in "pgoff" in the vm_fault structure. If it is possible that +the page may be truncated and/or invalidated, then the filesystem must lock +the page, then ensure it is not already truncated (the page lock will block +subsequent truncate), and then return with VM_FAULT_LOCKED, and the page +locked. The VM will unlock the page. + + ->page_mkwrite() is called when a previously read-only pte is +about to become writeable. The filesystem again must ensure that there are +no truncate/invalidate races, and then return with the page locked. If +the page has been truncated, the filesystem should not look up a new page +like the ->fault() handler, but simply return with VM_FAULT_NOPAGE, which +will cause the VM to retry the fault. ->access() is called when get_user_pages() fails in acces_process_vm(), typically used to debug a process through diff --git a/Documentation/filesystems/caching/cachefiles.txt b/Documentation/filesystems/caching/cachefiles.txt index c78a49b7bba6..748a1ae49e12 100644 --- a/Documentation/filesystems/caching/cachefiles.txt +++ b/Documentation/filesystems/caching/cachefiles.txt @@ -407,7 +407,7 @@ A NOTE ON SECURITY ================== CacheFiles makes use of the split security in the task_struct. It allocates -its own task_security structure, and redirects current->act_as to point to it +its own task_security structure, and redirects current->cred to point to it when it acts on behalf of another process, in that process's context. The reason it does this is that it calls vfs_mkdir() and suchlike rather than @@ -429,9 +429,9 @@ This means it may lose signals or ptrace events for example, and affects what the process looks like in /proc. So CacheFiles makes use of a logical split in the security between the -objective security (task->sec) and the subjective security (task->act_as). The -objective security holds the intrinsic security properties of a process and is -never overridden. This is what appears in /proc, and is what is used when a +objective security (task->real_cred) and the subjective security (task->cred). +The objective security holds the intrinsic security properties of a process and +is never overridden. This is what appears in /proc, and is what is used when a process is the target of an operation by some other process (SIGKILL for example). diff --git a/Documentation/filesystems/gfs2-glocks.txt b/Documentation/filesystems/gfs2-glocks.txt index 4dae9a3840bf..0494f78d87e4 100644 --- a/Documentation/filesystems/gfs2-glocks.txt +++ b/Documentation/filesystems/gfs2-glocks.txt @@ -60,7 +60,7 @@ go_lock | Called for the first local holder of a lock go_unlock | Called on the final local unlock of a lock go_dump | Called to print content of object for debugfs file, or on | error to dump glock to the log. -go_type; | The type of the glock, LM_TYPE_..... +go_type | The type of the glock, LM_TYPE_..... go_min_hold_time | The minimum hold time The minimum hold time for each lock is the time after a remote lock diff --git a/Documentation/filesystems/gfs2.txt b/Documentation/filesystems/gfs2.txt index 593004b6bbab..5e3ab8f3beff 100644 --- a/Documentation/filesystems/gfs2.txt +++ b/Documentation/filesystems/gfs2.txt @@ -11,18 +11,15 @@ their I/O so file system consistency is maintained. One of the nifty features of GFS is perfect consistency -- changes made to the file system on one machine show up immediately on all other machines in the cluster. -GFS uses interchangable inter-node locking mechanisms. Different lock -modules can plug into GFS and each file system selects the appropriate -lock module at mount time. Lock modules include: +GFS uses interchangable inter-node locking mechanisms, the currently +supported mechanisms are: lock_nolock -- allows gfs to be used as a local file system lock_dlm -- uses a distributed lock manager (dlm) for inter-node locking The dlm is found at linux/fs/dlm/ -In addition to interfacing with an external locking manager, a gfs lock -module is responsible for interacting with external cluster management -systems. Lock_dlm depends on user space cluster management systems found +Lock_dlm depends on user space cluster management systems found at the URL above. To use gfs as a local file system, no external clustering systems are @@ -31,13 +28,19 @@ needed, simply: $ mkfs -t gfs2 -p lock_nolock -j 1 /dev/block_device $ mount -t gfs2 /dev/block_device /dir -GFS2 is not on-disk compatible with previous versions of GFS. +If you are using Fedora, you need to install the gfs2-utils package +and, for lock_dlm, you will also need to install the cman package +and write a cluster.conf as per the documentation. + +GFS2 is not on-disk compatible with previous versions of GFS, but it +is pretty close. The following man pages can be found at the URL above: - gfs2_fsck to repair a filesystem + fsck.gfs2 to repair a filesystem gfs2_grow to expand a filesystem online gfs2_jadd to add journals to a filesystem online gfs2_tool to manipulate, examine and tune a filesystem gfs2_quota to examine and change quota values in a filesystem + gfs2_convert to convert a gfs filesystem to gfs2 in-place mount.gfs2 to help mount(8) mount a filesystem mkfs.gfs2 to make a filesystem diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt index 222437efd75a..3015da0c6b2a 100644 --- a/Documentation/filesystems/tmpfs.txt +++ b/Documentation/filesystems/tmpfs.txt @@ -133,4 +133,4 @@ RAM/SWAP in 10240 inodes and it is only accessible by root. Author: Christoph Rohland <cr@sap.com>, 1.12.01 Updated: - Hugh Dickins <hugh@veritas.com>, 4 June 2007 + Hugh Dickins, 4 June 2007 diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index deeeed0faa8f..f49eecf2e573 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -277,8 +277,7 @@ or bottom half). unfreeze_fs: called when VFS is unlocking a filesystem and making it writable again. - statfs: called when the VFS needs to get filesystem statistics. This - is called with the kernel lock held + 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 |