* [PATCH 1/4] doc: Update doc about journalling layer
2015-07-16 9:53 [PATCH 0/4 v2] Remove ext3 filesystem driver Jan Kara
@ 2015-07-16 9:53 ` Jan Kara
2015-07-16 9:53 ` [PATCH 2/4] fs: Remove ext3 filesystem driver Jan Kara
` (2 subsequent siblings)
3 siblings, 0 replies; 6+ messages in thread
From: Jan Kara @ 2015-07-16 9:53 UTC (permalink / raw)
To: linux-ext4
Cc: linux-fsdevel, LKML, Andrew Morton, Andreas Dilger, Jens Axboe,
Ted Tso, Jan Kara
Documentation of journalling layer in
Documentation/DocBook/filesystems.tmpl speaks about JBD layer. Since
that is going away, update the documentation to speak about JBD2. Also
update the parts that have changed since someone last touched the
document and remove some parts which are just misleading and outdated.
Signed-off-by: Jan Kara <jack@suse.com>
---
Documentation/DocBook/filesystems.tmpl | 178 +++++++++++++--------------------
1 file changed, 67 insertions(+), 111 deletions(-)
diff --git a/Documentation/DocBook/filesystems.tmpl b/Documentation/DocBook/filesystems.tmpl
index bcdfdb9a9277..6006b6358c86 100644
--- a/Documentation/DocBook/filesystems.tmpl
+++ b/Documentation/DocBook/filesystems.tmpl
@@ -146,36 +146,30 @@
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 journal_init_inode() call
-is for journals stored in filesystem inodes, or the journal_init_dev()
-call can be use for journal stored on a raw device (in a continuous range
+media on which the journal 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 journal_destroy() on it
+you are finally finished make sure you call jbd2_journal_destroy() on it
to free up any used kernel memory.
</para>
<para>
Once you have got your journal_t object you need to 'mount' or load the journal
-file, unless of course you haven't initialised it yet - in which case you
-need to call journal_create().
+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 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 jbd2_journal_wipe() to
+clear the journal contents before calling jbd2_journal_load().
</para>
<para>
-Most of the time however your journal file will already have been created, but
-before you load it you must call journal_wipe() to empty the journal file.
-Hang on, you say , what if the filesystem wasn't cleanly umount()'d . Well, it is the
-job of the client file system to detect this and skip the call to journal_wipe().
-</para>
-
-<para>
-In either case the next call should be to journal_load() which prepares the
-journal file for use. Note that journal_wipe(..,0) calls journal_skip_recovery()
-for you if it detects any outstanding transactions in the journal and similarly
-journal_load() will call journal_recover() if necessary.
-I would advise reading fs/ext3/super.c for examples on this stage.
-[RGG: Why is the journal_wipe() call necessary - doesn't this needlessly
-complicate the API. Or isn't a good idea for the journal layer to hide
-dirty mounts from the client fs]
+Note that jbd2_journal_wipe(..,0) calls 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.
</para>
<para>
@@ -189,41 +183,41 @@ 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 journal_start() which
+you are actually making are. To do this use jbd2_journal_start() which
returns a transaction handle.
</para>
<para>
-journal_start()
-and its counterpart 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 journal_stop() the same number of times as
-journal_start() before the transaction is completed (or more accurately
-leaves the update phase). Ext3/VFS makes use of this feature to simplify
-quota support.
+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 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.
</para>
<para>
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 journal_get_{create,write,undo}_access() as appropriate,
+need to call jbd2_journal_get_{create,write,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 journal_dirty_{meta,}data().
+you are have done so you need to call jbd2_journal_dirty_{meta,}data().
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 journal_forget()
+required to be pushed back on the device you can call jbd2_journal_forget()
in much the same way as you might have used bforget() in the past.
</para>
<para>
-A journal_flush() may be called at any time to commit and checkpoint
+A jbd2_journal_flush() may be called at any time to commit and checkpoint
all your transactions.
</para>
<para>
-Then at umount time , in your put_super() you can then call journal_destroy()
+Then at umount time , in your put_super() you can then call jbd2_journal_destroy()
to clean up your in-core journal object.
</para>
@@ -231,53 +225,68 @@ 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 journal_stop(). This means
+commits 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 ext3) may be modified in a later syscall.
+yours (say ext4) may be modified in a later syscall.
</para>
<para>
-The second case to bear in mind is that journal_start() can
+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 journal_stop(). So to avoid
-deadlocks you must treat journal_start/stop() as if they
+so essentially we are waiting for jbd2_journal_stop(). So to avoid
+deadlocks you must treat jbd2_journal_start/stop() as if they
were semaphores and include them in your semaphore ordering rules to prevent
-deadlocks. Note that journal_extend() has similar blocking behaviour to
-journal_start() so you can deadlock here just as easily as on 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().
</para>
<para>
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 transaction.
-I advise having a look at at least ext3_jbd.h to see the basis on which
-ext3 uses to make these decisions.
+I advise having a look at at least ext4_jbd.h to see the basis on which
+ext4 uses to make these decisions.
</para>
<para>
Another wriggle to watch out for is your on-disk block allocation strategy.
-why? Because, if you undo a delete, you need to ensure you haven't reused any
-of the freed blocks in a later transaction. One simple way of doing this
-is make sure any blocks you allocate only have checkpointed transactions
-listed against them. Ext3 does this in ext3_test_allocatable().
+Why? Because, if you do a delete, you need to ensure you haven't reused any
+of the freed blocks until the transaction freeing these blocks commits. If you
+reused these blocks and crash happens, there is no way to restore the contents
+of the reallocated blocks at the end of the last fully committed transaction.
+
+One simple way of doing this is to mark blocks as free in internal in-memory
+block allocation structures only after the transaction freeing them commits.
+Ext4 uses journal commit callback for this purpose.
+</para>
+
+<para>
+With journal commit callbacks you can ask the journalling layer to call a
+callback function when the transaction is finally committed to disk, so that
+you can do some of your own management. You ask the journalling layer for
+calling the callback by simply setting journal->j_commit_callback function
+pointer and that function is called after each transaction commit. You can also
+use transaction->t_private_list for attaching entries to a transaction that
+need processing when the transaction commits.
</para>
<para>
-Lock is also providing through journal_{un,}lock_updates(),
-ext3 uses this when it wants a window with a clean and stable fs for a moment.
-eg.
+JBD2 also provides a way to block all transaction updates via
+jbd2_journal_{un,}lock_updates(). Ext4 uses this when it wants a window with a
+clean and stable fs for a moment. E.g.
</para>
<programlisting>
- journal_lock_updates() //stop new stuff happening..
- journal_flush() // checkpoint everything.
+ jbd2_journal_lock_updates() //stop new stuff happening..
+ jbd2_journal_flush() // checkpoint everything.
..do stuff on stable fs
- journal_unlock_updates() // carry on with filesystem use.
+ jbd2_journal_unlock_updates() // carry on with filesystem use.
</programlisting>
<para>
@@ -286,29 +295,6 @@ if you allow unprivileged userspace to trigger codepaths containing these
calls.
</para>
-<para>
-A new feature of jbd since 2.5.25 is commit callbacks with the new
-journal_callback_set() function you can now ask the journalling layer
-to call you back when the transaction is finally committed to disk, so that
-you can do some of your own management. The key to this is the journal_callback
-struct, this maintains the internal callback information but you can
-extend it like this:-
-</para>
-<programlisting>
- struct myfs_callback_s {
- //Data structure element required by jbd..
- struct journal_callback for_jbd;
- // Stuff for myfs allocated together.
- myfs_inode* i_commited;
-
- }
-</programlisting>
-
-<para>
-this would be useful if you needed to know when data was committed to a
-particular inode.
-</para>
-
</sect2>
<sect2 id="jbd_summary">
@@ -319,36 +305,6 @@ being each mount, each modification (transaction) and each changed buffer
to tell the journalling layer about them.
</para>
-<para>
-Here is a some pseudo code to give you an idea of how it works, as
-an example.
-</para>
-
-<programlisting>
- journal_t* my_jnrl = journal_create();
- journal_init_{dev,inode}(jnrl,...)
- if (clean) journal_wipe();
- journal_load();
-
- foreach(transaction) { /*transactions must be
- completed before
- a syscall returns to
- userspace*/
-
- handle_t * xct=journal_start(my_jnrl);
- foreach(bh) {
- journal_get_{create,write,undo}_access(xact,bh);
- if ( myfs_modify(bh) ) { /* returns true
- if makes changes */
- journal_dirty_{meta,}data(xact,bh);
- } else {
- journal_forget(bh);
- }
- }
- journal_stop(xct);
- }
- journal_destroy(my_jrnl);
-</programlisting>
</sect2>
</sect1>
@@ -357,13 +313,13 @@ an example.
<title>Data Types</title>
<para>
The journalling layer uses typedefs to 'hide' the concrete definitions
- of the structures used. As a client of the JBD layer you can
+ of the structures used. As a client of the JBD2 layer you can
just rely on the using the pointer as a magic cookie of some sort.
Obviously the hiding is not enforced as this is 'C'.
</para>
<sect2 id="structures"><title>Structures</title>
-!Iinclude/linux/jbd.h
+!Iinclude/linux/jbd2.h
</sect2>
</sect1>
@@ -375,11 +331,11 @@ an example.
manage transactions
</para>
<sect2 id="journal_level"><title>Journal Level</title>
-!Efs/jbd/journal.c
-!Ifs/jbd/recovery.c
+!Efs/jbd2/journal.c
+!Ifs/jbd2/recovery.c
</sect2>
<sect2 id="transaction_level"><title>Transasction Level</title>
-!Efs/jbd/transaction.c
+!Efs/jbd2/transaction.c
</sect2>
</sect1>
<sect1 id="see_also">
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 2/4] fs: Remove ext3 filesystem driver
2015-07-16 9:53 [PATCH 0/4 v2] Remove ext3 filesystem driver Jan Kara
2015-07-16 9:53 ` [PATCH 1/4] doc: Update doc about journalling layer Jan Kara
@ 2015-07-16 9:53 ` Jan Kara
2015-07-16 9:53 ` [PATCH 3/4] block: Remove forced page bouncing under IO Jan Kara
2015-07-16 9:53 ` [PATCH 4/4] ext4: Improve ext4 Kconfig test Jan Kara
3 siblings, 0 replies; 6+ messages in thread
From: Jan Kara @ 2015-07-16 9:53 UTC (permalink / raw)
To: linux-ext4
Cc: linux-fsdevel, LKML, Andrew Morton, Andreas Dilger, Jens Axboe,
Ted Tso, Jan Kara
From: Jan Kara <jack@suse.cz>
The functionality of ext3 is fully supported by ext4 driver. Major
distributions (SUSE, RedHat) already use ext4 driver to handle ext3
filesystems for quite some time. There is some ugliness in mm resulting
from jbd cleaning buffers in a dirty page without cleaning page dirty
bit and also support for buffer bouncing in the block layer when stable
pages are required is there only because of jbd. So let's remove the
ext3 driver. This saves us some 28k lines of duplicated code.
Acked-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jan Kara <jack@suse.cz>
---
Documentation/filesystems/ext2.txt | 4 +-
Documentation/filesystems/ext3.txt | 209 +--
Documentation/filesystems/vfs.txt | 2 +-
MAINTAINERS | 18 +-
fs/Kconfig | 5 +-
fs/Makefile | 2 -
fs/ext3/Kconfig | 89 -
fs/ext3/Makefile | 12 -
fs/ext3/acl.c | 281 ---
fs/ext3/acl.h | 72 -
fs/ext3/balloc.c | 2158 ----------------------
fs/ext3/bitmap.c | 20 -
fs/ext3/dir.c | 537 ------
fs/ext3/ext3.h | 1332 --------------
fs/ext3/ext3_jbd.c | 59 -
fs/ext3/file.c | 79 -
fs/ext3/fsync.c | 109 --
fs/ext3/hash.c | 206 ---
fs/ext3/ialloc.c | 706 -------
fs/ext3/inode.c | 3574 ------------------------------------
fs/ext3/ioctl.c | 327 ----
fs/ext3/namei.c | 2586 --------------------------
fs/ext3/namei.h | 27 -
fs/ext3/resize.c | 1117 -----------
fs/ext3/super.c | 3165 -------------------------------
fs/ext3/symlink.c | 46 -
fs/ext3/xattr.c | 1330 --------------
fs/ext3/xattr.h | 136 --
fs/ext3/xattr_security.c | 78 -
fs/ext3/xattr_trusted.c | 54 -
fs/ext3/xattr_user.c | 58 -
fs/ext4/Kconfig | 41 +-
fs/ext4/super.c | 14 +-
fs/jbd/Kconfig | 30 -
fs/jbd/Makefile | 7 -
fs/jbd/checkpoint.c | 782 --------
fs/jbd/commit.c | 1021 ----------
fs/jbd/journal.c | 2145 ----------------------
fs/jbd/recovery.c | 594 ------
fs/jbd/revoke.c | 733 --------
fs/jbd/transaction.c | 2237 ----------------------
include/linux/jbd.h | 1047 -----------
include/linux/jbd2.h | 41 +-
include/linux/jbd_common.h | 46 -
include/trace/events/ext3.h | 866 ---------
include/trace/events/jbd.h | 194 --
46 files changed, 87 insertions(+), 28109 deletions(-)
delete mode 100644 fs/ext3/Kconfig
delete mode 100644 fs/ext3/Makefile
delete mode 100644 fs/ext3/acl.c
delete mode 100644 fs/ext3/acl.h
delete mode 100644 fs/ext3/balloc.c
delete mode 100644 fs/ext3/bitmap.c
delete mode 100644 fs/ext3/dir.c
delete mode 100644 fs/ext3/ext3.h
delete mode 100644 fs/ext3/ext3_jbd.c
delete mode 100644 fs/ext3/file.c
delete mode 100644 fs/ext3/fsync.c
delete mode 100644 fs/ext3/hash.c
delete mode 100644 fs/ext3/ialloc.c
delete mode 100644 fs/ext3/inode.c
delete mode 100644 fs/ext3/ioctl.c
delete mode 100644 fs/ext3/namei.c
delete mode 100644 fs/ext3/namei.h
delete mode 100644 fs/ext3/resize.c
delete mode 100644 fs/ext3/super.c
delete mode 100644 fs/ext3/symlink.c
delete mode 100644 fs/ext3/xattr.c
delete mode 100644 fs/ext3/xattr.h
delete mode 100644 fs/ext3/xattr_security.c
delete mode 100644 fs/ext3/xattr_trusted.c
delete mode 100644 fs/ext3/xattr_user.c
delete mode 100644 fs/jbd/Kconfig
delete mode 100644 fs/jbd/Makefile
delete mode 100644 fs/jbd/checkpoint.c
delete mode 100644 fs/jbd/commit.c
delete mode 100644 fs/jbd/journal.c
delete mode 100644 fs/jbd/recovery.c
delete mode 100644 fs/jbd/revoke.c
delete mode 100644 fs/jbd/transaction.c
delete mode 100644 include/linux/jbd.h
delete mode 100644 include/linux/jbd_common.h
delete mode 100644 include/trace/events/ext3.h
delete mode 100644 include/trace/events/jbd.h
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/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.
diff --git a/MAINTAINERS b/MAINTAINERS
index fd6078443083..d78655e61702 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -4058,15 +4058,6 @@ F: Documentation/filesystems/ext2.txt
F: fs/ext2/
F: include/linux/ext2*
-EXT3 FILE SYSTEM
-M: Jan Kara <jack@suse.cz>
-M: Andrew Morton <akpm@linux-foundation.org>
-M: Andreas Dilger <adilger.kernel@dilger.ca>
-L: linux-ext4@vger.kernel.org
-S: Maintained
-F: Documentation/filesystems/ext3.txt
-F: fs/ext3/
-
EXT4 FILE SYSTEM
M: "Theodore Ts'o" <tytso@mit.edu>
M: Andreas Dilger <adilger.kernel@dilger.ca>
@@ -5750,16 +5741,9 @@ S: Maintained
F: fs/jffs2/
F: include/uapi/linux/jffs2.h
-JOURNALLING LAYER FOR BLOCK DEVICES (JBD)
-M: Andrew Morton <akpm@linux-foundation.org>
-M: Jan Kara <jack@suse.cz>
-L: linux-ext4@vger.kernel.org
-S: Maintained
-F: fs/jbd/
-F: include/linux/jbd.h
-
JOURNALLING LAYER FOR BLOCK DEVICES (JBD2)
M: "Theodore Ts'o" <tytso@mit.edu>
+M: Jan Kara <jack@suse.cz>
L: linux-ext4@vger.kernel.org
S: Maintained
F: fs/jbd2/
diff --git a/fs/Kconfig b/fs/Kconfig
index 011f43365d7b..da3f32f1a4e4 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -11,18 +11,15 @@ config DCACHE_WORD_ACCESS
if BLOCK
source "fs/ext2/Kconfig"
-source "fs/ext3/Kconfig"
source "fs/ext4/Kconfig"
-source "fs/jbd/Kconfig"
source "fs/jbd2/Kconfig"
config FS_MBCACHE
# Meta block cache for Extended Attributes (ext2/ext3/ext4)
tristate
default y if EXT2_FS=y && EXT2_FS_XATTR
- default y if EXT3_FS=y && EXT3_FS_XATTR
default y if EXT4_FS=y
- default m if EXT2_FS_XATTR || EXT3_FS_XATTR || EXT4_FS
+ default m if EXT2_FS_XATTR || EXT4_FS
source "fs/reiserfs/Kconfig"
source "fs/jfs/Kconfig"
diff --git a/fs/Makefile b/fs/Makefile
index cb20e4bf2303..09e051fefc5b 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -62,12 +62,10 @@ obj-$(CONFIG_DLM) += dlm/
# Do not add any filesystems before this line
obj-$(CONFIG_FSCACHE) += fscache/
obj-$(CONFIG_REISERFS_FS) += reiserfs/
-obj-$(CONFIG_EXT3_FS) += ext3/ # Before ext2 so root fs can be ext3
obj-$(CONFIG_EXT2_FS) += ext2/
# We place ext4 after ext2 so plain ext2 root fs's are mounted using ext2
# unless explicitly requested by rootfstype
obj-$(CONFIG_EXT4_FS) += ext4/
-obj-$(CONFIG_JBD) += jbd/
obj-$(CONFIG_JBD2) += jbd2/
obj-$(CONFIG_CRAMFS) += cramfs/
obj-$(CONFIG_SQUASHFS) += squashfs/
diff --git a/fs/ext3/Kconfig b/fs/ext3/Kconfig
deleted file mode 100644
index e8c6ba0e4a3e..000000000000
diff --git a/fs/ext3/Makefile b/fs/ext3/Makefile
deleted file mode 100644
index e77766a8b3f0..000000000000
diff --git a/fs/ext3/acl.c b/fs/ext3/acl.c
deleted file mode 100644
index 8bbaf5bcf982..000000000000
diff --git a/fs/ext3/acl.h b/fs/ext3/acl.h
deleted file mode 100644
index ea1c69edab9e..000000000000
diff --git a/fs/ext3/balloc.c b/fs/ext3/balloc.c
deleted file mode 100644
index 158b5d4ce067..000000000000
diff --git a/fs/ext3/bitmap.c b/fs/ext3/bitmap.c
deleted file mode 100644
index ef9c643e8e9d..000000000000
diff --git a/fs/ext3/dir.c b/fs/ext3/dir.c
deleted file mode 100644
index 17742eed2c16..000000000000
diff --git a/fs/ext3/ext3.h b/fs/ext3/ext3.h
deleted file mode 100644
index f483a80b3fe7..000000000000
diff --git a/fs/ext3/ext3_jbd.c b/fs/ext3/ext3_jbd.c
deleted file mode 100644
index 785a3261a26c..000000000000
diff --git a/fs/ext3/file.c b/fs/ext3/file.c
deleted file mode 100644
index 3b8f650de22c..000000000000
diff --git a/fs/ext3/fsync.c b/fs/ext3/fsync.c
deleted file mode 100644
index 1cb9c7e10c6f..000000000000
diff --git a/fs/ext3/hash.c b/fs/ext3/hash.c
deleted file mode 100644
index ede315cdf126..000000000000
diff --git a/fs/ext3/ialloc.c b/fs/ext3/ialloc.c
deleted file mode 100644
index 3ad242e5840e..000000000000
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
deleted file mode 100644
index 6c7e5468a2f8..000000000000
diff --git a/fs/ext3/ioctl.c b/fs/ext3/ioctl.c
deleted file mode 100644
index 4d96e9a64532..000000000000
diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c
deleted file mode 100644
index c9e767cd4b67..000000000000
diff --git a/fs/ext3/namei.h b/fs/ext3/namei.h
deleted file mode 100644
index 46304d8c9f0a..000000000000
diff --git a/fs/ext3/resize.c b/fs/ext3/resize.c
deleted file mode 100644
index 27105655502c..000000000000
diff --git a/fs/ext3/super.c b/fs/ext3/super.c
deleted file mode 100644
index 5ed0044fbb37..000000000000
diff --git a/fs/ext3/symlink.c b/fs/ext3/symlink.c
deleted file mode 100644
index c08c59094ae6..000000000000
diff --git a/fs/ext3/xattr.c b/fs/ext3/xattr.c
deleted file mode 100644
index 7cf36501ccf4..000000000000
diff --git a/fs/ext3/xattr.h b/fs/ext3/xattr.h
deleted file mode 100644
index 32e93ebf8031..000000000000
diff --git a/fs/ext3/xattr_security.c b/fs/ext3/xattr_security.c
deleted file mode 100644
index c9506d5e3b13..000000000000
diff --git a/fs/ext3/xattr_trusted.c b/fs/ext3/xattr_trusted.c
deleted file mode 100644
index 206cc66dc285..000000000000
diff --git a/fs/ext3/xattr_user.c b/fs/ext3/xattr_user.c
deleted file mode 100644
index 021508ad1616..000000000000
diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index bf8bc8aba471..219a190ccae9 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -1,5 +1,38 @@
+# Ext3 configs are here for backward compatibility with old configs which may
+# have EXT3_FS set but not EXT4_FS set and thus would result in non-bootable
+# kernels after the removal of ext3 driver.
+config EXT3_FS
+ tristate "The Extended 3 (ext3) filesystem"
+ # These must match EXT4_FS selects...
+ select EXT4_FS
+ select JBD2
+ select CRC16
+ select CRYPTO
+ select CRYPTO_CRC32C
+ help
+ This config option is here only for backward compatibility. ext3
+ filesystem is now handled by the ext4 driver.
+
+config EXT3_FS_POSIX_ACL
+ bool "Ext3 POSIX Access Control Lists"
+ depends on EXT3_FS
+ select EXT4_FS_POSIX_ACL
+ select FS_POSIX_ACL
+ help
+ This config option is here only for backward compatibility. ext3
+ filesystem is now handled by the ext4 driver.
+
+config EXT3_FS_SECURITY
+ bool "Ext3 Security Labels"
+ depends on EXT3_FS
+ select EXT4_FS_SECURITY
+ help
+ This config option is here only for backward compatibility. ext3
+ filesystem is now handled by the ext4 driver.
+
config EXT4_FS
tristate "The Extended 4 (ext4) filesystem"
+ # Please update EXT3_FS selects when changing these
select JBD2
select CRC16
select CRYPTO
@@ -28,14 +61,14 @@ config EXT4_FS
If unsure, say N.
-config EXT4_USE_FOR_EXT23
+config EXT4_USE_FOR_EXT2
bool "Use ext4 for ext2/ext3 file systems"
depends on EXT4_FS
- depends on EXT3_FS=n || EXT2_FS=n
+ depends on EXT2_FS=n
default y
help
- Allow the ext4 file system driver code to be used for ext2 or
- ext3 file system mounts. This allows users to reduce their
+ Allow the ext4 file system driver code to be used for ext2
+ file system mounts. This allows users to reduce their
compiled kernel size by using one file system driver for
ext2, ext3, and ext4 file systems.
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 58987b5c514b..06b4b14e8aa0 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -84,7 +84,7 @@ static void ext4_unregister_li_request(struct super_block *sb);
static void ext4_clear_request_list(void);
static int ext4_reserve_clusters(struct ext4_sb_info *, ext4_fsblk_t);
-#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
+#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
static struct file_system_type ext2_fs_type = {
.owner = THIS_MODULE,
.name = "ext2",
@@ -100,7 +100,6 @@ MODULE_ALIAS("ext2");
#endif
-#if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
static struct file_system_type ext3_fs_type = {
.owner = THIS_MODULE,
.name = "ext3",
@@ -111,9 +110,6 @@ static struct file_system_type ext3_fs_type = {
MODULE_ALIAS_FS("ext3");
MODULE_ALIAS("ext3");
#define IS_EXT3_SB(sb) ((sb)->s_bdev->bd_holder == &ext3_fs_type)
-#else
-#define IS_EXT3_SB(sb) (0)
-#endif
static int ext4_verify_csum_type(struct super_block *sb,
struct ext4_super_block *es)
@@ -5500,7 +5496,7 @@ static struct dentry *ext4_mount(struct file_system_type *fs_type, int flags,
return mount_bdev(fs_type, flags, dev_name, data, ext4_fill_super);
}
-#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
+#if !defined(CONFIG_EXT2_FS) && !defined(CONFIG_EXT2_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT2)
static inline void register_as_ext2(void)
{
int err = register_filesystem(&ext2_fs_type);
@@ -5530,7 +5526,6 @@ static inline void unregister_as_ext2(void) { }
static inline int ext2_feature_set_ok(struct super_block *sb) { return 0; }
#endif
-#if !defined(CONFIG_EXT3_FS) && !defined(CONFIG_EXT3_FS_MODULE) && defined(CONFIG_EXT4_USE_FOR_EXT23)
static inline void register_as_ext3(void)
{
int err = register_filesystem(&ext3_fs_type);
@@ -5556,11 +5551,6 @@ static inline int ext3_feature_set_ok(struct super_block *sb)
return 0;
return 1;
}
-#else
-static inline void register_as_ext3(void) { }
-static inline void unregister_as_ext3(void) { }
-static inline int ext3_feature_set_ok(struct super_block *sb) { return 0; }
-#endif
static struct file_system_type ext4_fs_type = {
.owner = THIS_MODULE,
diff --git a/fs/jbd/Kconfig b/fs/jbd/Kconfig
deleted file mode 100644
index 4e28beeed157..000000000000
diff --git a/fs/jbd/Makefile b/fs/jbd/Makefile
deleted file mode 100644
index 54aca4868a36..000000000000
diff --git a/fs/jbd/checkpoint.c b/fs/jbd/checkpoint.c
deleted file mode 100644
index 08c03044abdd..000000000000
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
deleted file mode 100644
index bb217dcb41af..000000000000
diff --git a/fs/jbd/journal.c b/fs/jbd/journal.c
deleted file mode 100644
index c46a79adb6ad..000000000000
diff --git a/fs/jbd/recovery.c b/fs/jbd/recovery.c
deleted file mode 100644
index a748fe21465a..000000000000
diff --git a/fs/jbd/revoke.c b/fs/jbd/revoke.c
deleted file mode 100644
index dcead636c33b..000000000000
diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
deleted file mode 100644
index 1695ba8334a2..000000000000
diff --git a/include/linux/jbd.h b/include/linux/jbd.h
deleted file mode 100644
index d32615280be9..000000000000
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index edb640ae9a94..ad4b28647298 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -29,6 +29,7 @@
#include <linux/mutex.h>
#include <linux/timer.h>
#include <linux/slab.h>
+#include <linux/bit_spinlock.h>
#include <crypto/hash.h>
#endif
@@ -336,7 +337,45 @@ BUFFER_FNS(Freed, freed)
BUFFER_FNS(Shadow, shadow)
BUFFER_FNS(Verified, verified)
-#include <linux/jbd_common.h>
+static inline struct buffer_head *jh2bh(struct journal_head *jh)
+{
+ return jh->b_bh;
+}
+
+static inline struct journal_head *bh2jh(struct buffer_head *bh)
+{
+ return bh->b_private;
+}
+
+static inline void jbd_lock_bh_state(struct buffer_head *bh)
+{
+ bit_spin_lock(BH_State, &bh->b_state);
+}
+
+static inline int jbd_trylock_bh_state(struct buffer_head *bh)
+{
+ return bit_spin_trylock(BH_State, &bh->b_state);
+}
+
+static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
+{
+ return bit_spin_is_locked(BH_State, &bh->b_state);
+}
+
+static inline void jbd_unlock_bh_state(struct buffer_head *bh)
+{
+ bit_spin_unlock(BH_State, &bh->b_state);
+}
+
+static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
+{
+ bit_spin_lock(BH_JournalHead, &bh->b_state);
+}
+
+static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
+{
+ bit_spin_unlock(BH_JournalHead, &bh->b_state);
+}
#define J_ASSERT(assert) BUG_ON(!(assert))
diff --git a/include/linux/jbd_common.h b/include/linux/jbd_common.h
deleted file mode 100644
index 3dc53432355f..000000000000
diff --git a/include/trace/events/ext3.h b/include/trace/events/ext3.h
deleted file mode 100644
index fc733d28117a..000000000000
diff --git a/include/trace/events/jbd.h b/include/trace/events/jbd.h
deleted file mode 100644
index da6f2591c25e..000000000000
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 3/4] block: Remove forced page bouncing under IO
2015-07-16 9:53 [PATCH 0/4 v2] Remove ext3 filesystem driver Jan Kara
2015-07-16 9:53 ` [PATCH 1/4] doc: Update doc about journalling layer Jan Kara
2015-07-16 9:53 ` [PATCH 2/4] fs: Remove ext3 filesystem driver Jan Kara
@ 2015-07-16 9:53 ` Jan Kara
2015-07-16 9:53 ` [PATCH 4/4] ext4: Improve ext4 Kconfig test Jan Kara
3 siblings, 0 replies; 6+ messages in thread
From: Jan Kara @ 2015-07-16 9:53 UTC (permalink / raw)
To: linux-ext4
Cc: linux-fsdevel, LKML, Andrew Morton, Andreas Dilger, Jens Axboe,
Ted Tso, Jan Kara
From: Jan Kara <jack@suse.cz>
JBD layer wrote back data buffers without setting PageWriteback bit.
Thus standard mechanism for guaranteeing stable pages under IO did not
work. Since JBD is gone now and there is no other user of the
functionality, just remove it.
Acked-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Jan Kara <jack@suse.cz>
---
block/bounce.c | 31 ++++---------------------------
include/linux/blk_types.h | 5 ++---
2 files changed, 6 insertions(+), 30 deletions(-)
diff --git a/block/bounce.c b/block/bounce.c
index b17311227c12..31cad13a0c9d 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -176,26 +176,8 @@ static void bounce_end_io_read_isa(struct bio *bio, int err)
__bounce_end_io_read(bio, isa_page_pool, err);
}
-#ifdef CONFIG_NEED_BOUNCE_POOL
-static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
-{
- if (bio_data_dir(bio) != WRITE)
- return 0;
-
- if (!bdi_cap_stable_pages_required(&q->backing_dev_info))
- return 0;
-
- return test_bit(BIO_SNAP_STABLE, &bio->bi_flags);
-}
-#else
-static int must_snapshot_stable_pages(struct request_queue *q, struct bio *bio)
-{
- return 0;
-}
-#endif /* CONFIG_NEED_BOUNCE_POOL */
-
static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
- mempool_t *pool, int force)
+ mempool_t *pool)
{
struct bio *bio;
int rw = bio_data_dir(*bio_orig);
@@ -203,8 +185,6 @@ static void __blk_queue_bounce(struct request_queue *q, struct bio **bio_orig,
struct bvec_iter iter;
unsigned i;
- if (force)
- goto bounce;
bio_for_each_segment(from, *bio_orig, iter)
if (page_to_pfn(from.bv_page) > queue_bounce_pfn(q))
goto bounce;
@@ -216,7 +196,7 @@ bounce:
bio_for_each_segment_all(to, bio, i) {
struct page *page = to->bv_page;
- if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)
+ if (page_to_pfn(page) <= queue_bounce_pfn(q))
continue;
to->bv_page = mempool_alloc(pool, q->bounce_gfp);
@@ -254,7 +234,6 @@ bounce:
void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
{
- int must_bounce;
mempool_t *pool;
/*
@@ -263,15 +242,13 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
if (!bio_has_data(*bio_orig))
return;
- must_bounce = must_snapshot_stable_pages(q, *bio_orig);
-
/*
* for non-isa bounce case, just check if the bounce pfn is equal
* to or bigger than the highest pfn in the system -- in that case,
* don't waste time iterating over bio segments
*/
if (!(q->bounce_gfp & GFP_DMA)) {
- if (queue_bounce_pfn(q) >= blk_max_pfn && !must_bounce)
+ if (queue_bounce_pfn(q) >= blk_max_pfn)
return;
pool = page_pool;
} else {
@@ -282,7 +259,7 @@ void blk_queue_bounce(struct request_queue *q, struct bio **bio_orig)
/*
* slow path
*/
- __blk_queue_bounce(q, bio_orig, pool, must_bounce);
+ __blk_queue_bounce(q, bio_orig, pool);
}
EXPORT_SYMBOL(blk_queue_bounce);
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 7303b3405520..89fd49184b48 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -118,9 +118,8 @@ struct bio {
#define BIO_USER_MAPPED 4 /* contains user pages */
#define BIO_NULL_MAPPED 5 /* contains invalid user pages */
#define BIO_QUIET 6 /* Make BIO Quiet */
-#define BIO_SNAP_STABLE 7 /* bio data must be snapshotted during write */
-#define BIO_CHAIN 8 /* chained bio, ->bi_remaining in effect */
-#define BIO_REFFED 9 /* bio has elevated ->bi_cnt */
+#define BIO_CHAIN 7 /* chained bio, ->bi_remaining in effect */
+#define BIO_REFFED 8 /* bio has elevated ->bi_cnt */
/*
* Flags starting here get preserved by bio_reset() - this includes
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* [PATCH 4/4] ext4: Improve ext4 Kconfig test
2015-07-16 9:53 [PATCH 0/4 v2] Remove ext3 filesystem driver Jan Kara
` (2 preceding siblings ...)
2015-07-16 9:53 ` [PATCH 3/4] block: Remove forced page bouncing under IO Jan Kara
@ 2015-07-16 9:53 ` Jan Kara
2015-07-16 13:59 ` Theodore Ts'o
3 siblings, 1 reply; 6+ messages in thread
From: Jan Kara @ 2015-07-16 9:53 UTC (permalink / raw)
To: linux-ext4
Cc: linux-fsdevel, LKML, Andrew Morton, Andreas Dilger, Jens Axboe,
Ted Tso, Jan Kara
Now that ext4 driver must be used to access ext3 filesystems, improve
the Kconfig help text to better explain that using ext4 driver to access
the filesystem is fully compatible with the old ext3 driver.
Signed-off-by: Jan Kara <jack@suse.com>
---
fs/ext4/Kconfig | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/ext4/Kconfig b/fs/ext4/Kconfig
index 219a190ccae9..47728da7702c 100644
--- a/fs/ext4/Kconfig
+++ b/fs/ext4/Kconfig
@@ -49,12 +49,13 @@ config EXT4_FS
up fsck time. For more information, please see the web pages at
http://ext4.wiki.kernel.org.
- The ext4 filesystem will support mounting an ext3
- filesystem; while there will be some performance gains from
- the delayed allocation and inode table readahead, the best
- performance gains will require enabling ext4 features in the
- filesystem, or formatting a new filesystem as an ext4
- filesystem initially.
+ The ext4 filesystem supports mounting an ext3 filesystem; while there
+ are some performance gains from the delayed allocation and inode
+ table readahead, the best performance gains require enabling ext4
+ features in the filesystem using tune2fs, or formatting a new
+ filesystem as an ext4 filesystem initially. Without explicit enabling
+ of ext4 features, the on disk filesystem format stays fully backward
+ compatible.
To compile this file system support as a module, choose M here. The
module will be called ext4.
--
2.1.4
^ permalink raw reply related [flat|nested] 6+ messages in thread* Re: [PATCH 4/4] ext4: Improve ext4 Kconfig test
2015-07-16 9:53 ` [PATCH 4/4] ext4: Improve ext4 Kconfig test Jan Kara
@ 2015-07-16 13:59 ` Theodore Ts'o
0 siblings, 0 replies; 6+ messages in thread
From: Theodore Ts'o @ 2015-07-16 13:59 UTC (permalink / raw)
To: Jan Kara
Cc: linux-ext4, linux-fsdevel, LKML, Andrew Morton, Andreas Dilger,
Jens Axboe
On Thu, Jul 16, 2015 at 11:53:06AM +0200, Jan Kara wrote:
> Now that ext4 driver must be used to access ext3 filesystems, improve
> the Kconfig help text to better explain that using ext4 driver to access
> the filesystem is fully compatible with the old ext3 driver.
>
> Signed-off-by: Jan Kara <jack@suse.com>
Acked-by: Theodore Ts'o <tytso@mit.edu>
- Ted
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