diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/Locking | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/nfs/Exporting | 38 | ||||
| -rw-r--r-- | Documentation/filesystems/nfs/nfs-rdma.txt | 16 | ||||
| -rw-r--r-- | Documentation/filesystems/seq_file.txt | 33 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 3 |
5 files changed, 72 insertions, 24 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index b18dd1779029..f1997e9da61f 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -349,7 +349,11 @@ prototypes: locking rules: inode->i_lock may block fl_copy_lock: yes no -fl_release_private: maybe no +fl_release_private: maybe maybe[1] + +[1]: ->fl_release_private for flock or POSIX locks is currently allowed +to block. Leases however can still be freed while the i_lock is held and +so fl_release_private called on a lease should not block. ----------------------- lock_manager_operations --------------------------- prototypes: diff --git a/Documentation/filesystems/nfs/Exporting b/Documentation/filesystems/nfs/Exporting index e543b1a619cc..c8f036a9b13f 100644 --- a/Documentation/filesystems/nfs/Exporting +++ b/Documentation/filesystems/nfs/Exporting @@ -66,23 +66,31 @@ b/ A per-superblock list "s_anon" of dentries which are the roots of c/ Helper routines to allocate anonymous dentries, and to help attach loose directory dentries at lookup time. They are: - d_alloc_anon(inode) will return a dentry for the given inode. + d_obtain_alias(inode) will return a dentry for the given inode. If the inode already has a dentry, one of those is returned. If it doesn't, a new anonymous (IS_ROOT and DCACHE_DISCONNECTED) dentry is allocated and attached. In the case of a directory, care is taken that only one dentry can ever be attached. - d_splice_alias(inode, dentry) will make sure that there is a - dentry with the same name and parent as the given dentry, and - which refers to the given inode. - If the inode is a directory and already has a dentry, then that - dentry is d_moved over the given dentry. - If the passed dentry gets attached, care is taken that this is - mutually exclusive to a d_alloc_anon operation. - If the passed dentry is used, NULL is returned, else the used - dentry is returned. This corresponds to the calling pattern of - ->lookup. - + d_splice_alias(inode, dentry) or d_materialise_unique(dentry, inode) + will introduce a new dentry into the tree; either the passed-in + dentry or a preexisting alias for the given inode (such as an + anonymous one created by d_obtain_alias), if appropriate. The two + functions differ in their handling of directories with preexisting + aliases: + d_splice_alias will use any existing IS_ROOT dentry, but it will + return -EIO rather than try to move a dentry with a different + parent. This is appropriate for local filesystems, which + should never see such an alias unless the filesystem is + corrupted somehow (for example, if two on-disk directory + entries refer to the same directory.) + d_materialise_unique will attempt to move any dentry. This is + appropriate for distributed filesystems, where finding a + directory other than where we last cached it may be a normal + consequence of concurrent operations on other hosts. + Both functions return NULL when the passed-in dentry is used, + following the calling convention of ->lookup. + Filesystem Issues ----------------- @@ -120,12 +128,12 @@ struct which has the following members: fh_to_dentry (mandatory) Given a filehandle fragment, this should find the implied object and - create a dentry for it (possibly with d_alloc_anon). + create a dentry for it (possibly with d_obtain_alias). fh_to_parent (optional but strongly recommended) Given a filehandle fragment, this should find the parent of the - implied object and create a dentry for it (possibly with d_alloc_anon). - May fail if the filehandle fragment is too small. + implied object and create a dentry for it (possibly with + d_obtain_alias). May fail if the filehandle fragment is too small. get_parent (optional but strongly recommended) When given a dentry for a directory, this should return a dentry for diff --git a/Documentation/filesystems/nfs/nfs-rdma.txt b/Documentation/filesystems/nfs/nfs-rdma.txt index e386f7e4bcee..724043858b08 100644 --- a/Documentation/filesystems/nfs/nfs-rdma.txt +++ b/Documentation/filesystems/nfs/nfs-rdma.txt @@ -138,9 +138,9 @@ Installation - Build, install, reboot The NFS/RDMA code will be enabled automatically if NFS and RDMA - are turned on. The NFS/RDMA client and server are configured via the hidden - SUNRPC_XPRT_RDMA config option that depends on SUNRPC and INFINIBAND. The - value of SUNRPC_XPRT_RDMA will be: + are turned on. The NFS/RDMA client and server are configured via the + SUNRPC_XPRT_RDMA_CLIENT and SUNRPC_XPRT_RDMA_SERVER config options that both + depend on SUNRPC and INFINIBAND. The default value of both options will be: - N if either SUNRPC or INFINIBAND are N, in this case the NFS/RDMA client and server will not be built @@ -235,8 +235,9 @@ NFS/RDMA Setup - Start the NFS server - If the NFS/RDMA server was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in - kernel config), load the RDMA transport module: + If the NFS/RDMA server was built as a module + (CONFIG_SUNRPC_XPRT_RDMA_SERVER=m in kernel config), load the RDMA + transport module: $ modprobe svcrdma @@ -255,8 +256,9 @@ NFS/RDMA Setup - On the client system - If the NFS/RDMA client was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in - kernel config), load the RDMA client module: + If the NFS/RDMA client was built as a module + (CONFIG_SUNRPC_XPRT_RDMA_CLIENT=m in kernel config), load the RDMA client + module: $ modprobe xprtrdma.ko diff --git a/Documentation/filesystems/seq_file.txt b/Documentation/filesystems/seq_file.txt index 1fe0ccb1af55..8ea3e90ace07 100644 --- a/Documentation/filesystems/seq_file.txt +++ b/Documentation/filesystems/seq_file.txt @@ -235,6 +235,39 @@ be used for more than one file, you can store an arbitrary pointer in the private field of the seq_file structure; that value can then be retrieved by the iterator functions. +There is also a wrapper function to seq_open() called seq_open_private(). It +kmallocs a zero filled block of memory and stores a pointer to it in the +private field of the seq_file structure, returning 0 on success. The +block size is specified in a third parameter to the function, e.g.: + + static int ct_open(struct inode *inode, struct file *file) + { + return seq_open_private(file, &ct_seq_ops, + sizeof(struct mystruct)); + } + +There is also a variant function, __seq_open_private(), which is functionally +identical except that, if successful, it returns the pointer to the allocated +memory block, allowing further initialisation e.g.: + + static int ct_open(struct inode *inode, struct file *file) + { + struct mystruct *p = + __seq_open_private(file, &ct_seq_ops, sizeof(*p)); + + if (!p) + return -ENOMEM; + + p->foo = bar; /* initialize my stuff */ + ... + p->baz = true; + + return 0; + } + +A corresponding close function, seq_release_private() is available which +frees the memory allocated in the corresponding open. + The other operations of interest - read(), llseek(), and release() - are all implemented by the seq_file code itself. So a virtual file's file_operations structure will look like: diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index a1d0d7a30165..61d65cc65c54 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -1053,7 +1053,8 @@ struct dentry_operations { If the 'rcu_walk' parameter is true, then the caller is doing a pathwalk in RCU-walk mode. Sleeping is not permitted in this mode, and the caller can be asked to leave it and call again by returning - -ECHILD. + -ECHILD. -EISDIR may also be returned to tell pathwalk to + ignore d_automount or any mounts. This function is only used if DCACHE_MANAGE_TRANSIT is set on the dentry being transited from. |