diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/dlmfs.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/f2fs.rst | 6 | ||||
| -rw-r--r-- | Documentation/filesystems/journalling.rst | 66 | ||||
| -rw-r--r-- | Documentation/filesystems/ocfs2.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.rst | 11 | ||||
| -rw-r--r-- | Documentation/filesystems/quota.rst | 12 | ||||
| -rw-r--r-- | Documentation/filesystems/tmpfs.rst | 18 | ||||
| -rw-r--r-- | Documentation/filesystems/udf.rst | 2 | ||||
| -rw-r--r-- | Documentation/filesystems/zonefs.rst | 22 |
9 files changed, 79 insertions, 62 deletions
diff --git a/Documentation/filesystems/dlmfs.rst b/Documentation/filesystems/dlmfs.rst index 68daaa7facf9..28dd41a63be2 100644 --- a/Documentation/filesystems/dlmfs.rst +++ b/Documentation/filesystems/dlmfs.rst @@ -12,7 +12,7 @@ dlmfs is built with OCFS2 as it requires most of its infrastructure. :Project web page: http://ocfs2.wiki.kernel.org :Tools web page: https://github.com/markfasheh/ocfs2-tools -:OCFS2 mailing lists: http://oss.oracle.com/projects/ocfs2/mailman/ +:OCFS2 mailing lists: https://oss.oracle.com/projects/ocfs2/mailman/ All code copyright 2005 Oracle except when otherwise noted. diff --git a/Documentation/filesystems/f2fs.rst b/Documentation/filesystems/f2fs.rst index a11d329542f9..ec8d99703ecb 100644 --- a/Documentation/filesystems/f2fs.rst +++ b/Documentation/filesystems/f2fs.rst @@ -258,6 +258,8 @@ compress_extension=%s Support adding specified extension, so that f2fs can enab on compression extension list and enable compression on these file by default rather than to enable it via ioctl. For other files, we can still enable compression via ioctl. + Note that, there is one reserved special extension '*', it + can be set to enable compression for all files. inlinecrypt When possible, encrypt/decrypt the contents of encrypted files using the blk-crypto framework rather than filesystem-layer encryption. This allows the use of @@ -743,8 +745,8 @@ Compression implementation - In order to eliminate write amplification during overwrite, F2FS only support compression on write-once file, data can be compressed only when - all logical blocks in file are valid and cluster compress ratio is lower - than specified threshold. + all logical blocks in cluster contain valid data and compress ratio of + cluster data is lower than specified threshold. - To enable compression on regular inode, there are three ways: diff --git a/Documentation/filesystems/journalling.rst b/Documentation/filesystems/journalling.rst index 58ce6b395206..7e2be2faf653 100644 --- a/Documentation/filesystems/journalling.rst +++ b/Documentation/filesystems/journalling.rst @@ -10,27 +10,27 @@ Details The journalling layer is easy to use. You need to first of all create a journal_t data structure. There are two calls to do this dependent on how you decide to allocate the physical media on which the journal -resides. The :c:func:`jbd2_journal_init_inode` call is for journals stored in -filesystem inodes, or the :c:func:`jbd2_journal_init_dev` call can be used +resides. The jbd2_journal_init_inode() call is for journals stored in +filesystem inodes, or the jbd2_journal_init_dev() call can be used for journal stored on a raw device (in a continuous range of blocks). A journal_t is a typedef for a struct pointer, so when you are finally -finished make sure you call :c:func:`jbd2_journal_destroy` on it to free up +finished make sure you call jbd2_journal_destroy() on it to free up any used kernel memory. Once you have got your journal_t object you need to 'mount' or load the journal file. The journalling layer expects the space for the journal was already allocated and initialized properly by the userspace tools. -When loading the journal you must call :c:func:`jbd2_journal_load` to process +When loading the journal you must call jbd2_journal_load() to process journal contents. If the client file system detects the journal contents does not need to be processed (or even need not have valid contents), it -may call :c:func:`jbd2_journal_wipe` to clear the journal contents before -calling :c:func:`jbd2_journal_load`. +may call jbd2_journal_wipe() to clear the journal contents before +calling jbd2_journal_load(). Note that jbd2_journal_wipe(..,0) calls -:c:func:`jbd2_journal_skip_recovery` for you if it detects any outstanding -transactions in the journal and similarly :c:func:`jbd2_journal_load` will -call :c:func:`jbd2_journal_recover` if necessary. I would advise reading -:c:func:`ext4_load_journal` in fs/ext4/super.c for examples on this stage. +jbd2_journal_skip_recovery() for you if it detects any outstanding +transactions in the journal and similarly jbd2_journal_load() will +call jbd2_journal_recover() if necessary. I would advise reading +ext4_load_journal() in fs/ext4/super.c for examples on this stage. Now you can go ahead and start modifying the underlying filesystem. Almost. @@ -39,57 +39,57 @@ You still need to actually journal your filesystem changes, this is done by wrapping them into transactions. Additionally you also need to wrap the modification of each of the buffers with calls to the journal layer, so it knows what the modifications you are actually making are. To do -this use :c:func:`jbd2_journal_start` which returns a transaction handle. +this use jbd2_journal_start() which returns a transaction handle. -:c:func:`jbd2_journal_start` and its counterpart :c:func:`jbd2_journal_stop`, +jbd2_journal_start() and its counterpart jbd2_journal_stop(), which indicates the end of a transaction are nestable calls, so you can reenter a transaction if necessary, but remember you must call -:c:func:`jbd2_journal_stop` the same number of times as -:c:func:`jbd2_journal_start` before the transaction is completed (or more +jbd2_journal_stop() the same number of times as +jbd2_journal_start() before the transaction is completed (or more accurately leaves the update phase). Ext4/VFS makes use of this feature to simplify handling of inode dirtying, quota support, etc. Inside each transaction you need to wrap the modifications to the individual buffers (blocks). Before you start to modify a buffer you -need to call :c:func:`jbd2_journal_get_create_access()` / -:c:func:`jbd2_journal_get_write_access()` / -:c:func:`jbd2_journal_get_undo_access()` as appropriate, this allows the +need to call jbd2_journal_get_create_access() / +jbd2_journal_get_write_access() / +jbd2_journal_get_undo_access() as appropriate, this allows the journalling layer to copy the unmodified data if it needs to. After all the buffer may be part of a previously uncommitted transaction. At this point you are at last ready to modify a buffer, and once you are have done so you need to call -:c:func:`jbd2_journal_dirty_metadata`. Or if you've asked for access to a +jbd2_journal_dirty_metadata(). Or if you've asked for access to a buffer you now know is now longer required to be pushed back on the -device you can call :c:func:`jbd2_journal_forget` in much the same way as you -might have used :c:func:`bforget` in the past. +device you can call jbd2_journal_forget() in much the same way as you +might have used bforget() in the past. -A :c:func:`jbd2_journal_flush` may be called at any time to commit and +A jbd2_journal_flush() may be called at any time to commit and checkpoint all your transactions. -Then at umount time , in your :c:func:`put_super` you can then call -:c:func:`jbd2_journal_destroy` to clean up your in-core journal object. +Then at umount time , in your put_super() you can then call +jbd2_journal_destroy() to clean up your in-core journal object. Unfortunately there a couple of ways the journal layer can cause a deadlock. The first thing to note is that each task can only have a single outstanding transaction at any one time, remember nothing commits -until the outermost :c:func:`jbd2_journal_stop`. This means you must complete +until the outermost jbd2_journal_stop(). This means you must complete the transaction at the end of each file/inode/address etc. operation you perform, so that the journalling system isn't re-entered on another journal. Since transactions can't be nested/batched across differing journals, and another filesystem other than yours (say ext4) may be modified in a later syscall. -The second case to bear in mind is that :c:func:`jbd2_journal_start` can block +The second case to bear in mind is that jbd2_journal_start() can block if there isn't enough space in the journal for your transaction (based on the passed nblocks param) - when it blocks it merely(!) needs to wait for transactions to complete and be committed from other tasks, so -essentially we are waiting for :c:func:`jbd2_journal_stop`. So to avoid -deadlocks you must treat :c:func:`jbd2_journal_start` / -:c:func:`jbd2_journal_stop` as if they were semaphores and include them in +essentially we are waiting for jbd2_journal_stop(). So to avoid +deadlocks you must treat jbd2_journal_start() / +jbd2_journal_stop() as if they were semaphores and include them in your semaphore ordering rules to prevent -deadlocks. Note that :c:func:`jbd2_journal_extend` has similar blocking -behaviour to :c:func:`jbd2_journal_start` so you can deadlock here just as -easily as on :c:func:`jbd2_journal_start`. +deadlocks. Note that jbd2_journal_extend() has similar blocking +behaviour to jbd2_journal_start() so you can deadlock here just as +easily as on jbd2_journal_start(). Try to reserve the right number of blocks the first time. ;-). This will be the maximum number of blocks you are going to touch in this @@ -116,8 +116,8 @@ called after each transaction commit. You can also use that need processing when the transaction commits. JBD2 also provides a way to block all transaction updates via -:c:func:`jbd2_journal_lock_updates()` / -:c:func:`jbd2_journal_unlock_updates()`. Ext4 uses this when it wants a +jbd2_journal_lock_updates() / +jbd2_journal_unlock_updates(). Ext4 uses this when it wants a window with a clean and stable fs for a moment. E.g. :: diff --git a/Documentation/filesystems/ocfs2.rst b/Documentation/filesystems/ocfs2.rst index 412386bc6506..42ca9a3d4c6e 100644 --- a/Documentation/filesystems/ocfs2.rst +++ b/Documentation/filesystems/ocfs2.rst @@ -14,7 +14,7 @@ get "mount.ocfs2" and "ocfs2_hb_ctl". Project web page: http://ocfs2.wiki.kernel.org Tools git tree: https://github.com/markfasheh/ocfs2-tools -OCFS2 mailing lists: http://oss.oracle.com/projects/ocfs2/mailman/ +OCFS2 mailing lists: https://oss.oracle.com/projects/ocfs2/mailman/ All code copyright 2005 Oracle except when otherwise noted. diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst index e024a9efffd8..533c79e8d2cd 100644 --- a/Documentation/filesystems/proc.rst +++ b/Documentation/filesystems/proc.rst @@ -1633,9 +1633,6 @@ may allocate from based on an estimation of its current memory and swap use. For example, if a task is using all allowed memory, its badness score will be 1000. If it is using half of its allowed memory, its score will be 500. -There is an additional factor included in the badness score: the current memory -and swap usage is discounted by 3% for root processes. - The amount of "allowed" memory depends on the context in which the oom killer was called. If it is due to the memory assigned to the allocating task's cpuset being exhausted, the allowed memory represents the set of mems assigned to that @@ -1671,11 +1668,6 @@ The value of /proc/<pid>/oom_score_adj may be reduced no lower than the last value set by a CAP_SYS_RESOURCE process. To reduce the value any lower requires CAP_SYS_RESOURCE. -Caveat: when a parent task is selected, the oom killer will sacrifice any first -generation children with separate address spaces instead, if possible. This -avoids servers and important system daemons from being killed and loses the -minimal amount of work. - 3.2 /proc/<pid>/oom_score - Display current oom-killer score ------------------------------------------------------------- @@ -1684,6 +1676,9 @@ This file can be used to check the current score used by the oom-killer for any given <pid>. Use it together with /proc/<pid>/oom_score_adj to tune which process should be killed in an out-of-memory situation. +Please note that the exported value includes oom_score_adj so it is +effectively in range [0,2000]. + 3.3 /proc/<pid>/io - Display the IO accounting fields ------------------------------------------------------- diff --git a/Documentation/filesystems/quota.rst b/Documentation/filesystems/quota.rst index a30cdd47c652..abd4303c546e 100644 --- a/Documentation/filesystems/quota.rst +++ b/Documentation/filesystems/quota.rst @@ -18,7 +18,7 @@ Quota limits (and amount of grace time) are set independently for each filesystem. For more details about quota design, see the documentation in quota-tools package -(http://sourceforge.net/projects/linuxquota). +(https://sourceforge.net/projects/linuxquota). Quota netlink interface ======================= @@ -31,11 +31,11 @@ the above events to userspace. There they can be captured by an application and processed accordingly. The interface uses generic netlink framework (see -http://lwn.net/Articles/208755/ and http://people.suug.ch/~tgr/libnl/ for more -details about this layer). The name of the quota generic netlink interface -is "VFS_DQUOT". Definitions of constants below are in <linux/quota.h>. -Since the quota netlink protocol is not namespace aware, quota netlink messages -are sent only in initial network namespace. +https://lwn.net/Articles/208755/ and http://www.infradead.org/~tgr/libnl/ for +more details about this layer). The name of the quota generic netlink interface +is "VFS_DQUOT". Definitions of constants below are in <linux/quota.h>. Since +the quota netlink protocol is not namespace aware, quota netlink messages are +sent only in initial network namespace. Currently, the interface supports only one message type QUOTA_NL_C_WARNING. This command is used to send a notification about any of the above mentioned diff --git a/Documentation/filesystems/tmpfs.rst b/Documentation/filesystems/tmpfs.rst index 4e95929301a5..c44f8b1d3cab 100644 --- a/Documentation/filesystems/tmpfs.rst +++ b/Documentation/filesystems/tmpfs.rst @@ -150,6 +150,22 @@ These options do not have any effect on remount. You can change these parameters with chmod(1), chown(1) and chgrp(1) on a mounted filesystem. +tmpfs has a mount option to select whether it will wrap at 32- or 64-bit inode +numbers: + +======= ======================== +inode64 Use 64-bit inode numbers +inode32 Use 32-bit inode numbers +======= ======================== + +On a 32-bit kernel, inode32 is implicit, and inode64 is refused at mount time. +On a 64-bit kernel, CONFIG_TMPFS_INODE64 sets the default. inode64 avoids the +possibility of multiple files with the same inode number on a single device; +but risks glibc failing with EOVERFLOW once 33-bit inode numbers are reached - +if a long-lived tmpfs is accessed by 32-bit applications so ancient that +opening a file larger than 2GiB fails with EINVAL. + + So 'mount -t tmpfs -o size=10G,nr_inodes=10k,mode=700 tmpfs /mytmpfs' will give you tmpfs instance on /mytmpfs which can allocate 10GB RAM/SWAP in 10240 inodes and it is only accessible by root. @@ -161,3 +177,5 @@ RAM/SWAP in 10240 inodes and it is only accessible by root. Hugh Dickins, 4 June 2007 :Updated: KOSAKI Motohiro, 16 Mar 2010 +:Updated: + Chris Down, 13 July 2020 diff --git a/Documentation/filesystems/udf.rst b/Documentation/filesystems/udf.rst index d9badbf285b2..f9489ddbb767 100644 --- a/Documentation/filesystems/udf.rst +++ b/Documentation/filesystems/udf.rst @@ -72,4 +72,4 @@ For the latest version and toolset see: Documentation on UDF and ECMA 167 is available FREE from: - http://www.osta.org/ - - http://www.ecma-international.org/ + - https://www.ecma-international.org/ diff --git a/Documentation/filesystems/zonefs.rst b/Documentation/filesystems/zonefs.rst index 71d845c6a700..6c18bc8ce332 100644 --- a/Documentation/filesystems/zonefs.rst +++ b/Documentation/filesystems/zonefs.rst @@ -110,14 +110,14 @@ contain files named "0", "1", "2", ... The file numbers also represent increasing zone start sector on the device. All read and write operations to zone files are not allowed beyond the file -maximum size, that is, beyond the zone size. Any access exceeding the zone -size is failed with the -EFBIG error. +maximum size, that is, beyond the zone capacity. Any access exceeding the zone +capacity is failed with the -EFBIG error. Creating, deleting, renaming or modifying any attribute of files and sub-directories is not allowed. The number of blocks of a file as reported by stat() and fstat() indicates the -size of the file zone, or in other words, the maximum file size. +capacity of the zone file, or in other words, the maximum file size. Conventional zone files ----------------------- @@ -156,8 +156,8 @@ all accepted. Truncating sequential zone files is allowed only down to 0, in which case, the zone is reset to rewind the file zone write pointer position to the start of -the zone, or up to the zone size, in which case the file's zone is transitioned -to the FULL state (finish zone operation). +the zone, or up to the zone capacity, in which case the file's zone is +transitioned to the FULL state (finish zone operation). Format options -------------- @@ -324,7 +324,7 @@ file size set to 0. This is necessary as the write pointer of read-only zones is defined as invalib by the ZBC and ZAC standards, making it impossible to discover the amount of data that has been written to the zone. In the case of a read-only zone discovered at run-time, as indicated in the previous section. -the size of the zone file is left unchanged from its last updated value. +The size of the zone file is left unchanged from its last updated value. Zonefs User Space Tools ======================= @@ -401,8 +401,9 @@ append-writes to the file:: # ls -l /mnt/seq/0 -rw-r----- 1 root root 0 Nov 25 13:49 /mnt/seq/0 -Since files are statically mapped to zones on the disk, the number of blocks of -a file as reported by stat() and fstat() indicates the size of the file zone:: +Since files are statically mapped to zones on the disk, the number of blocks +of a file as reported by stat() and fstat() indicates the capacity of the file +zone:: # stat /mnt/seq/0 File: /mnt/seq/0 @@ -416,5 +417,6 @@ a file as reported by stat() and fstat() indicates the size of the file zone:: The number of blocks of the file ("Blocks") in units of 512B blocks gives the maximum file size of 524288 * 512 B = 256 MB, corresponding to the device zone -size in this example. Of note is that the "IO block" field always indicates the -minimum I/O size for writes and corresponds to the device physical sector size. +capacity in this example. Of note is that the "IO block" field always +indicates the minimum I/O size for writes and corresponds to the device +physical sector size. |