diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/Locking | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/nfs/pnfs.txt | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/ntfs.txt | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/porting | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/romfs.txt | 3 | ||||
| -rw-r--r-- | Documentation/filesystems/sysfs.txt | 16 | ||||
| -rw-r--r-- | Documentation/filesystems/ubifs.txt | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 62 |
8 files changed, 63 insertions, 44 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 4471a416c274..2e994efe12cb 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -166,13 +166,11 @@ prototypes: void (*kill_sb) (struct super_block *); locking rules: may block -get_sb yes mount yes kill_sb yes -->get_sb() returns error or 0 with locked superblock attached to the vfsmount -(exclusive on ->s_umount). -->mount() returns ERR_PTR or the root dentry. +->mount() returns ERR_PTR or the root dentry; its superblock should be locked +on return. ->kill_sb() takes a write-locked superblock, does all shutdown work on it, unlocks and drops the reference. diff --git a/Documentation/filesystems/nfs/pnfs.txt b/Documentation/filesystems/nfs/pnfs.txt index bc0b9cfe095b..983e14abe7e9 100644 --- a/Documentation/filesystems/nfs/pnfs.txt +++ b/Documentation/filesystems/nfs/pnfs.txt @@ -46,3 +46,10 @@ data server cache file driver devices refer to data servers, which are kept in a module level cache. Its reference is held over the lifetime of the deviceid pointing to it. + +lseg +---- +lseg maintains an extra reference corresponding to the NFS_LSEG_VALID +bit which holds it in the pnfs_layout_hdr's list. When the final lseg +is removed from the pnfs_layout_hdr's list, the NFS_LAYOUT_DESTROYED +bit is set, preventing any new lsegs from being added. diff --git a/Documentation/filesystems/ntfs.txt b/Documentation/filesystems/ntfs.txt index 6ef8cf3bc9a3..933bc66ccff1 100644 --- a/Documentation/filesystems/ntfs.txt +++ b/Documentation/filesystems/ntfs.txt @@ -460,6 +460,8 @@ Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog. 2.1.30: - Fix writev() (it kept writing the first segment over and over again instead of moving onto subsequent segments). + - Fix crash in ntfs_mft_record_alloc() when mapping the new extent mft + record failed. 2.1.29: - Fix a deadlock when mounting read-write. 2.1.28: diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting index dfbcd1b00b0a..0c986c9e8519 100644 --- a/Documentation/filesystems/porting +++ b/Documentation/filesystems/porting @@ -394,3 +394,10 @@ file) you must return -EOPNOTSUPP if FALLOC_FL_PUNCH_HOLE is set in mode. Currently you can only have FALLOC_FL_PUNCH_HOLE with FALLOC_FL_KEEP_SIZE set, so the i_size should not change when hole punching, even when puching the end of a file off. + +-- +[mandatory] + ->get_sb() is gone. Switch to use of ->mount(). Typically it's just +a matter of switching from calling get_sb_... to mount_... and changing the +function type. If you were doing it manually, just switch from setting ->mnt_root +to some pointer to returning that pointer. On errors return ERR_PTR(...). diff --git a/Documentation/filesystems/romfs.txt b/Documentation/filesystems/romfs.txt index 2d2a7b2a16b9..e2b07cc9120a 100644 --- a/Documentation/filesystems/romfs.txt +++ b/Documentation/filesystems/romfs.txt @@ -17,8 +17,7 @@ comparison, an actual rescue disk used up 3202 blocks with ext2, while with romfs, it needed 3079 blocks. To create such a file system, you'll need a user program named -genromfs. It is available via anonymous ftp on sunsite.unc.edu and -its mirrors, in the /pub/Linux/system/recovery/ directory. +genromfs. It is available on http://romfs.sourceforge.net/ As the name suggests, romfs could be also used (space-efficiently) on various read-only media, like (E)EPROM disks if someone will have the diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt index 5d1335faec2d..f806e50aaa63 100644 --- a/Documentation/filesystems/sysfs.txt +++ b/Documentation/filesystems/sysfs.txt @@ -39,10 +39,12 @@ userspace. Top-level directories in sysfs represent the common ancestors of object hierarchies; i.e. the subsystems the objects belong to. -Sysfs internally stores the kobject that owns the directory in the -->d_fsdata pointer of the directory's dentry. This allows sysfs to do -reference counting directly on the kobject when the file is opened and -closed. +Sysfs internally stores a pointer to the kobject that implements a +directory in the sysfs_dirent object associated with the directory. In +the past this kobject pointer has been used by sysfs to do reference +counting directly on the kobject whenever the file is opened or closed. +With the current sysfs implementation the kobject reference count is +only modified directly by the function sysfs_schedule_callback(). Attributes @@ -208,9 +210,9 @@ Other notes: is 4096. - show() methods should return the number of bytes printed into the - buffer. This is the return value of snprintf(). + buffer. This is the return value of scnprintf(). -- show() should always use snprintf(). +- show() should always use scnprintf(). - store() should return the number of bytes used from the buffer. If the entire buffer has been used, just return the count argument. @@ -229,7 +231,7 @@ A very simple (and naive) implementation of a device attribute is: static ssize_t show_name(struct device *dev, struct device_attribute *attr, char *buf) { - return snprintf(buf, PAGE_SIZE, "%s\n", dev->name); + return scnprintf(buf, PAGE_SIZE, "%s\n", dev->name); } static ssize_t store_name(struct device *dev, struct device_attribute *attr, diff --git a/Documentation/filesystems/ubifs.txt b/Documentation/filesystems/ubifs.txt index 12fedb7834c6..d7b13b01e980 100644 --- a/Documentation/filesystems/ubifs.txt +++ b/Documentation/filesystems/ubifs.txt @@ -82,12 +82,12 @@ Mount options bulk_read read more in one go to take advantage of flash media that read faster sequentially no_bulk_read (*) do not bulk-read -no_chk_data_crc skip checking of CRCs on data nodes in order to +no_chk_data_crc (*) skip checking of CRCs on data nodes in order to improve read performance. Use this option only if the flash media is highly reliable. The effect of this option is that corruption of the contents of a file can go unnoticed. -chk_data_crc (*) do not skip checking CRCs on data nodes +chk_data_crc do not skip checking CRCs on data nodes compr=none override default compressor and set it to "none" compr=lzo override default compressor and set it to "lzo" compr=zlib override default compressor and set it to "zlib" diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 94cf97b901d7..306f0ae8df09 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -95,10 +95,11 @@ functions: extern int unregister_filesystem(struct file_system_type *); The passed struct file_system_type describes your filesystem. When a -request is made to mount a device onto a directory in your filespace, -the VFS will call the appropriate get_sb() method for the specific -filesystem. The dentry for the mount point will then be updated to -point to the root inode for the new filesystem. +request is made to mount a filesystem onto a directory in your namespace, +the VFS will call the appropriate mount() method for the specific +filesystem. New vfsmount refering to the tree returned by ->mount() +will be attached to the mountpoint, so that when pathname resolution +reaches the mountpoint it will jump into the root of that vfsmount. You can see all filesystems that are registered to the kernel in the file /proc/filesystems. @@ -107,14 +108,14 @@ file /proc/filesystems. struct file_system_type ----------------------- -This describes the filesystem. As of kernel 2.6.22, the following +This describes the filesystem. As of kernel 2.6.39, the following members are defined: struct file_system_type { const char *name; int fs_flags; - int (*get_sb) (struct file_system_type *, int, - const char *, void *, struct vfsmount *); + struct dentry (*mount) (struct file_system_type *, int, + const char *, void *); void (*kill_sb) (struct super_block *); struct module *owner; struct file_system_type * next; @@ -128,11 +129,11 @@ struct file_system_type { fs_flags: various flags (i.e. FS_REQUIRES_DEV, FS_NO_DCACHE, etc.) - get_sb: the method to call when a new instance of this + mount: the method to call when a new instance of this filesystem should be mounted kill_sb: the method to call when an instance of this filesystem - should be unmounted + should be shut down owner: for internal VFS use: you should initialize this to THIS_MODULE in most cases. @@ -141,7 +142,7 @@ struct file_system_type { s_lock_key, s_umount_key: lockdep-specific -The get_sb() method has the following arguments: +The mount() method has the following arguments: struct file_system_type *fs_type: describes the filesystem, partly initialized by the specific filesystem code @@ -153,32 +154,39 @@ The get_sb() method has the following arguments: void *data: arbitrary mount options, usually comes as an ASCII string (see "Mount Options" section) - struct vfsmount *mnt: a vfs-internal representation of a mount point +The mount() method must return the root dentry of the tree requested by +caller. An active reference to its superblock must be grabbed and the +superblock must be locked. On failure it should return ERR_PTR(error). -The get_sb() method must determine if the block device specified -in the dev_name and fs_type contains a filesystem of the type the method -supports. If it succeeds in opening the named block device, it initializes a -struct super_block descriptor for the filesystem contained by the block device. -On failure it returns an error. +The arguments match those of mount(2) and their interpretation +depends on filesystem type. E.g. for block filesystems, dev_name is +interpreted as block device name, that device is opened and if it +contains a suitable filesystem image the method creates and initializes +struct super_block accordingly, returning its root dentry to caller. + +->mount() may choose to return a subtree of existing filesystem - it +doesn't have to create a new one. The main result from the caller's +point of view is a reference to dentry at the root of (sub)tree to +be attached; creation of new superblock is a common side effect. The most interesting member of the superblock structure that the -get_sb() method fills in is the "s_op" field. This is a pointer to +mount() method fills in is the "s_op" field. This is a pointer to a "struct super_operations" which describes the next level of the filesystem implementation. -Usually, a filesystem uses one of the generic get_sb() implementations -and provides a fill_super() method instead. The generic methods are: +Usually, a filesystem uses one of the generic mount() implementations +and provides a fill_super() callback instead. The generic variants are: - get_sb_bdev: mount a filesystem residing on a block device + mount_bdev: mount a filesystem residing on a block device - get_sb_nodev: mount a filesystem that is not backed by a device + mount_nodev: mount a filesystem that is not backed by a device - get_sb_single: mount a filesystem which shares the instance between + mount_single: mount a filesystem which shares the instance between all mounts -A fill_super() method implementation has the following arguments: +A fill_super() callback implementation has the following arguments: - struct super_block *sb: the superblock structure. The method fill_super() + struct super_block *sb: the superblock structure. The callback must initialize this properly. void *data: arbitrary mount options, usually comes as an ASCII @@ -865,7 +873,7 @@ struct dentry_operations { void (*d_iput)(struct dentry *, struct inode *); char *(*d_dname)(struct dentry *, char *, int); struct vfsmount *(*d_automount)(struct path *); - int (*d_manage)(struct dentry *, bool, bool); + int (*d_manage)(struct dentry *, bool); }; d_revalidate: called when the VFS needs to revalidate a dentry. This @@ -961,10 +969,6 @@ struct dentry_operations { mounted on it and not to check the automount flag. Any other error code will abort pathwalk completely. - If the 'mounting_here' parameter is true, then namespace_sem is being - held by the caller and the function should not initiate any mounts or - unmounts that it will then wait for. - 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 returing |