diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/btrfs.txt | 16 | ||||
| -rw-r--r-- | Documentation/filesystems/debugfs.txt | 40 | ||||
| -rw-r--r-- | Documentation/filesystems/ext2.txt | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/ext3.txt | 209 | ||||
| -rw-r--r-- | Documentation/filesystems/f2fs.txt | 4 | ||||
| -rw-r--r-- | Documentation/filesystems/nfs/nfs-rdma.txt | 16 | ||||
| -rw-r--r-- | Documentation/filesystems/sysfs.txt | 5 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 2 |
8 files changed, 68 insertions, 228 deletions
diff --git a/Documentation/filesystems/btrfs.txt b/Documentation/filesystems/btrfs.txt index d11cc2f8077b..c772b47e7ef0 100644 --- a/Documentation/filesystems/btrfs.txt +++ b/Documentation/filesystems/btrfs.txt @@ -61,7 +61,7 @@ Options with (*) are default options and will not show in the mount options. check_int enables the integrity checker module, which examines all block write requests to ensure on-disk consistency, at a large - memory and CPU cost. + memory and CPU cost. check_int_data includes extent data in the integrity checks, and implies the check_int option. @@ -113,7 +113,7 @@ Options with (*) are default options and will not show in the mount options. Disable/enable debugging option to be more verbose in some ENOSPC conditions. fatal_errors=<action> - Action to take when encountering a fatal error: + Action to take when encountering a fatal error: "bug" - BUG() on a fatal error. This is the default. "panic" - panic() on a fatal error. @@ -132,10 +132,10 @@ Options with (*) are default options and will not show in the mount options. max_inline=<bytes> Specify the maximum amount of space, in bytes, that can be inlined in - a metadata B-tree leaf. The value is specified in bytes, optionally + a metadata B-tree leaf. The value is specified in bytes, optionally with a K, M, or G suffix, case insensitive. In practice, this value is limited by the root sector size, with some space unavailable due - to leaf headers. For a 4k sectorsize, max inline data is ~3900 bytes. + to leaf headers. For a 4k sector size, max inline data is ~3900 bytes. metadata_ratio=<value> Specify that 1 metadata chunk should be allocated after every <value> @@ -170,7 +170,7 @@ Options with (*) are default options and will not show in the mount options. recovery Enable autorecovery attempts if a bad tree root is found at mount time. - Currently this scans a list of several previous tree roots and tries to + Currently this scans a list of several previous tree roots and tries to use the first readable. rescan_uuid_tree @@ -194,7 +194,7 @@ Options with (*) are default options and will not show in the mount options. ssd_spread Options to control ssd allocation schemes. By default, BTRFS will enable or disable ssd allocation heuristics depending on whether a - rotational or nonrotational disk is in use. The ssd and nossd options + rotational or non-rotational disk is in use. The ssd and nossd options can override this autodetection. The ssd_spread mount option attempts to allocate into big chunks @@ -216,13 +216,13 @@ Options with (*) are default options and will not show in the mount options. This allows mounting of subvolumes which are not in the root of the mounted filesystem. You can use "btrfs subvolume show " to see the object ID for a subvolume. - + thread_pool=<number> The number of worker threads to allocate. The default number is equal to the number of CPUs + 2, or 8, whichever is smaller. user_subvol_rm_allowed - Allow subvolumes to be deleted by a non-root user. Use with caution. + Allow subvolumes to be deleted by a non-root user. Use with caution. MAILING LIST ============ diff --git a/Documentation/filesystems/debugfs.txt b/Documentation/filesystems/debugfs.txt index 88ab81c79109..463f595733e8 100644 --- a/Documentation/filesystems/debugfs.txt +++ b/Documentation/filesystems/debugfs.txt @@ -51,6 +51,17 @@ operations should be provided; others can be included as needed. Again, the return value will be a dentry pointer to the created file, NULL for error, or ERR_PTR(-ENODEV) if debugfs support is missing. +Create a file with an initial size, the following function can be used +instead: + + struct dentry *debugfs_create_file_size(const char *name, umode_t mode, + struct dentry *parent, void *data, + const struct file_operations *fops, + loff_t file_size); + +file_size is the initial file size. The other parameters are the same +as the function debugfs_create_file. + In a number of cases, the creation of a set of file operations is not actually necessary; the debugfs code provides a number of helper functions for simple situations. Files containing a single integer value can be @@ -100,6 +111,14 @@ A read on the resulting file will yield either Y (for non-zero values) or N, followed by a newline. If written to, it will accept either upper- or lower-case values, or 1 or 0. Any other input will be silently ignored. +Also, atomic_t values can be placed in debugfs with: + + struct dentry *debugfs_create_atomic_t(const char *name, umode_t mode, + struct dentry *parent, atomic_t *value) + +A read of this file will get atomic_t values, and a write of this file +will set atomic_t values. + Another option is exporting a block of arbitrary binary data, with this structure and function: @@ -147,6 +166,27 @@ The "base" argument may be 0, but you may want to build the reg32 array using __stringify, and a number of register names (macros) are actually byte offsets over a base for the register block. +If you want to dump an u32 array in debugfs, you can create file with: + + struct dentry *debugfs_create_u32_array(const char *name, umode_t mode, + struct dentry *parent, + u32 *array, u32 elements); + +The "array" argument provides data, and the "elements" argument is +the number of elements in the array. Note: Once array is created its +size can not be changed. + +There is a helper function to create device related seq_file: + + struct dentry *debugfs_create_devm_seqfile(struct device *dev, + const char *name, + struct dentry *parent, + int (*read_fn)(struct seq_file *s, + void *data)); + +The "dev" argument is the device related to this debugfs file, and +the "read_fn" is a function pointer which to be called to print the +seq_file content. There are a couple of other directory-oriented helper functions: diff --git a/Documentation/filesystems/ext2.txt b/Documentation/filesystems/ext2.txt index b9714569e472..55755395d3dc 100644 --- a/Documentation/filesystems/ext2.txt +++ b/Documentation/filesystems/ext2.txt @@ -360,8 +360,8 @@ and are copied into the filesystem. If a transaction is incomplete at the time of the crash, then there is no guarantee of consistency for the blocks in that transaction so they are discarded (which means any filesystem changes they represent are also lost). -Check Documentation/filesystems/ext3.txt if you want to read more about -ext3 and journaling. +Check Documentation/filesystems/ext4.txt if you want to read more about +ext4 and journaling. References ========== diff --git a/Documentation/filesystems/ext3.txt b/Documentation/filesystems/ext3.txt index 7ed0d17d6721..58758fbef9e0 100644 --- a/Documentation/filesystems/ext3.txt +++ b/Documentation/filesystems/ext3.txt @@ -6,210 +6,7 @@ Ext3 was originally released in September 1999. Written by Stephen Tweedie for the 2.2 branch, and ported to 2.4 kernels by Peter Braam, Andreas Dilger, Andrew Morton, Alexander Viro, Ted Ts'o and Stephen Tweedie. -Ext3 is the ext2 filesystem enhanced with journalling capabilities. +Ext3 is the ext2 filesystem enhanced with journalling capabilities. The +filesystem is a subset of ext4 filesystem so use ext4 driver for accessing +ext3 filesystems. -Options -======= - -When mounting an ext3 filesystem, the following option are accepted: -(*) == default - -ro Mount filesystem read only. Note that ext3 will replay - the journal (and thus write to the partition) even when - mounted "read only". Mount options "ro,noload" can be - used to prevent writes to the filesystem. - -journal=update Update the ext3 file system's journal to the current - format. - -journal=inum When a journal already exists, this option is ignored. - Otherwise, it specifies the number of the inode which - will represent the ext3 file system's journal file. - -journal_path=path -journal_dev=devnum When the external journal device's major/minor numbers - have changed, these options allow the user to specify - the new journal location. The journal device is - identified through either its new major/minor numbers - encoded in devnum, or via a path to the device. - -norecovery Don't load the journal on mounting. Note that this forces -noload mount of inconsistent filesystem, which can lead to - various problems. - -data=journal All data are committed into the journal prior to being - written into the main file system. - -data=ordered (*) All data are forced directly out to the main file - system prior to its metadata being committed to the - journal. - -data=writeback Data ordering is not preserved, data may be written - into the main file system after its metadata has been - committed to the journal. - -commit=nrsec (*) Ext3 can be told to sync all its data and metadata - every 'nrsec' seconds. The default value is 5 seconds. - This means that if you lose your power, you will lose - as much as the latest 5 seconds of work (your - filesystem will not be damaged though, thanks to the - journaling). This default value (or any low value) - will hurt performance, but it's good for data-safety. - Setting it to 0 will have the same effect as leaving - it at the default (5 seconds). - Setting it to very large values will improve - performance. - -barrier=<0|1(*)> This enables/disables the use of write barriers in -barrier (*) the jbd code. barrier=0 disables, barrier=1 enables. -nobarrier This also requires an IO stack which can support - barriers, and if jbd gets an error on a barrier - write, it will disable again with a warning. - Write barriers enforce proper on-disk ordering - of journal commits, making volatile disk write caches - safe to use, at some performance penalty. If - your disks are battery-backed in one way or another, - disabling barriers may safely improve performance. - The mount options "barrier" and "nobarrier" can - also be used to enable or disable barriers, for - consistency with other ext3 mount options. - -user_xattr Enables Extended User Attributes. Additionally, you - need to have extended attribute support enabled in the - kernel configuration (CONFIG_EXT3_FS_XATTR). See the - attr(5) manual page and http://acl.bestbits.at/ to - learn more about extended attributes. - -nouser_xattr Disables Extended User Attributes. - -acl Enables POSIX Access Control Lists support. - Additionally, you need to have ACL support enabled in - the kernel configuration (CONFIG_EXT3_FS_POSIX_ACL). - See the acl(5) manual page and http://acl.bestbits.at/ - for more information. - -noacl This option disables POSIX Access Control List - support. - -reservation - -noreservation - -bsddf (*) Make 'df' act like BSD. -minixdf Make 'df' act like Minix. - -check=none Don't do extra checking of bitmaps on mount. -nocheck - -debug Extra debugging information is sent to syslog. - -errors=remount-ro Remount the filesystem read-only on an error. -errors=continue Keep going on a filesystem error. -errors=panic Panic and halt the machine if an error occurs. - (These mount options override the errors behavior - specified in the superblock, which can be - configured using tune2fs.) - -data_err=ignore(*) Just print an error message if an error occurs - in a file data buffer in ordered mode. -data_err=abort Abort the journal if an error occurs in a file - data buffer in ordered mode. - -grpid Give objects the same group ID as their creator. -bsdgroups - -nogrpid (*) New objects have the group ID of their creator. -sysvgroups - -resgid=n The group ID which may use the reserved blocks. - -resuid=n The user ID which may use the reserved blocks. - -sb=n Use alternate superblock at this location. - -quota These options are ignored by the filesystem. They -noquota are used only by quota tools to recognize volumes -grpquota where quota should be turned on. See documentation -usrquota in the quota-tools package for more details - (http://sourceforge.net/projects/linuxquota). - -jqfmt=<quota type> These options tell filesystem details about quota -usrjquota=<file> so that quota information can be properly updated -grpjquota=<file> during journal replay. They replace the above - quota options. See documentation in the quota-tools - package for more details - (http://sourceforge.net/projects/linuxquota). - -Specification -============= -Ext3 shares all disk implementation with the ext2 filesystem, and adds -transactions capabilities to ext2. Journaling is done by the Journaling Block -Device layer. - -Journaling Block Device layer ------------------------------ -The Journaling Block Device layer (JBD) isn't ext3 specific. It was designed -to add journaling capabilities to a block device. The ext3 filesystem code -will inform the JBD of modifications it is performing (called a transaction). -The journal supports the transactions start and stop, and in case of a crash, -the journal can replay the transactions to quickly put the partition back into -a consistent state. - -Handles represent a single atomic update to a filesystem. JBD can handle an -external journal on a block device. - -Data Mode ---------- -There are 3 different data modes: - -* writeback mode -In data=writeback mode, ext3 does not journal data at all. This mode provides -a similar level of journaling as that of XFS, JFS, and ReiserFS in its default -mode - metadata journaling. A crash+recovery can cause incorrect data to -appear in files which were written shortly before the crash. This mode will -typically provide the best ext3 performance. - -* ordered mode -In data=ordered mode, ext3 only officially journals metadata, but it logically -groups metadata and data blocks into a single unit called a transaction. When -it's time to write the new metadata out to disk, the associated data blocks -are written first. In general, this mode performs slightly slower than -writeback but significantly faster than journal mode. - -* journal mode -data=journal mode provides full data and metadata journaling. All new data is -written to the journal first, and then to its final location. -In the event of a crash, the journal can be replayed, bringing both data and -metadata into a consistent state. This mode is the slowest except when data -needs to be read from and written to disk at the same time where it -outperforms all other modes. - -Compatibility -------------- - -Ext2 partitions can be easily convert to ext3, with `tune2fs -j <dev>`. -Ext3 is fully compatible with Ext2. Ext3 partitions can easily be mounted as -Ext2. - - -External Tools -============== -See manual pages to learn more. - -tune2fs: create a ext3 journal on a ext2 partition with the -j flag. -mke2fs: create a ext3 partition with the -j flag. -debugfs: ext2 and ext3 file system debugger. -ext2online: online (mounted) ext2 and ext3 filesystem resizer - - -References -========== - -kernel source: <file:fs/ext3/> - <file:fs/jbd/> - -programs: http://e2fsprogs.sourceforge.net/ - http://ext2resize.sourceforge.net - -useful links: http://www.ibm.com/developerworks/library/l-fs7/index.html - http://www.ibm.com/developerworks/library/l-fs8/index.html diff --git a/Documentation/filesystems/f2fs.txt b/Documentation/filesystems/f2fs.txt index e9e750e59efc..e2d5105b7214 100644 --- a/Documentation/filesystems/f2fs.txt +++ b/Documentation/filesystems/f2fs.txt @@ -143,7 +143,9 @@ fastboot This option is used when a system wants to reduce mount extent_cache Enable an extent cache based on rb-tree, it can cache as many as extent which map between contiguous logical address and physical address per inode, resulting in - increasing the cache hit ratio. + increasing the cache hit ratio. Set by default. +noextent_cache Diable an extent cache based on rb-tree explicitly, see + the above extent_cache mount option. noinline_data Disable the inline data feature, inline data feature is enabled by default. diff --git a/Documentation/filesystems/nfs/nfs-rdma.txt b/Documentation/filesystems/nfs/nfs-rdma.txt index 95c13aa575ff..906b6c233f62 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 - 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: + 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: - N if either SUNRPC or INFINIBAND are N, in this case the NFS/RDMA client and server will not be built @@ -238,9 +238,8 @@ NFS/RDMA Setup - Start the NFS server - If the NFS/RDMA server was built as a module - (CONFIG_SUNRPC_XPRT_RDMA_SERVER=m in kernel config), load the RDMA - transport module: + If the NFS/RDMA server was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in + kernel config), load the RDMA transport module: $ modprobe svcrdma @@ -259,9 +258,8 @@ NFS/RDMA Setup - On the client system - If the NFS/RDMA client was built as a module - (CONFIG_SUNRPC_XPRT_RDMA_CLIENT=m in kernel config), load the RDMA client - module: + If the NFS/RDMA client was built as a module (CONFIG_SUNRPC_XPRT_RDMA=m in + kernel config), load the RDMA client module: $ modprobe xprtrdma.ko diff --git a/Documentation/filesystems/sysfs.txt b/Documentation/filesystems/sysfs.txt index b35a64b82f9e..9494afb9476a 100644 --- a/Documentation/filesystems/sysfs.txt +++ b/Documentation/filesystems/sysfs.txt @@ -212,7 +212,10 @@ Other notes: - show() methods should return the number of bytes printed into the buffer. This is the return value of scnprintf(). -- show() should always use scnprintf(). +- show() must not use snprintf() when formatting the value to be + returned to user space. If you can guarantee that an overflow + will never happen you can use sprintf() otherwise you must 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. diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index 5eb8456fc41e..8c6f07ad373a 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -769,7 +769,7 @@ struct address_space_operations { to stall to allow flushers a chance to complete some IO. Ordinarily it can use PageDirty and PageWriteback but some filesystems have more complex state (unstable pages in NFS prevent reclaim) or - do not set those flags due to locking problems (jbd). This callback + do not set those flags due to locking problems. This callback allows a filesystem to indicate to the VM if a page should be treated as dirty or writeback for the purposes of stalling. |