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-rw-r--r--Documentation/filesystems/ext4.txt25
1 files changed, 21 insertions, 4 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 80e193d82e2e..eb154ef36c2a 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -26,9 +26,15 @@ Mailing list: linux-ext4@vger.kernel.org
26 26
27 git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git 27 git://git.kernel.org/pub/scm/fs/ext2/e2fsprogs.git
28 28
29 - Create a new filesystem using the ext4dev filesystem type: 29 - Note that it is highly important to install the mke2fs.conf file
30 that comes with the e2fsprogs 1.41.x sources in /etc/mke2fs.conf. If
31 you have edited the /etc/mke2fs.conf file installed on your system,
32 you will need to merge your changes with the version from e2fsprogs
33 1.41.x.
30 34
31 # mke2fs -t ext4dev /dev/hda1 35 - Create a new filesystem using the ext4 filesystem type:
36
37 # mke2fs -t ext4 /dev/hda1
32 38
33 Or configure an existing ext3 filesystem to support extents and set 39 Or configure an existing ext3 filesystem to support extents and set
34 the test_fs flag to indicate that it's ok for an in-development 40 the test_fs flag to indicate that it's ok for an in-development
@@ -41,13 +47,13 @@ Mailing list: linux-ext4@vger.kernel.org
41 47
42 # tune2fs -I 256 /dev/hda1 48 # tune2fs -I 256 /dev/hda1
43 49
44 (Note: we currently do not have tools to convert an ext4dev 50 (Note: we currently do not have tools to convert an ext4
45 filesystem back to ext3; so please do not do try this on production 51 filesystem back to ext3; so please do not do try this on production
46 filesystems.) 52 filesystems.)
47 53
48 - Mounting: 54 - Mounting:
49 55
50 # mount -t ext4dev /dev/hda1 /wherever 56 # mount -t ext4 /dev/hda1 /wherever
51 57
52 - When comparing performance with other filesystems, remember that 58 - When comparing performance with other filesystems, remember that
53 ext3/4 by default offers higher data integrity guarantees than most. 59 ext3/4 by default offers higher data integrity guarantees than most.
@@ -171,6 +177,11 @@ barrier=<0|1(*)> This enables/disables the use of write barriers in
171 your disks are battery-backed in one way or another, 177 your disks are battery-backed in one way or another,
172 disabling barriers may safely improve performance. 178 disabling barriers may safely improve performance.
173 179
180inode_readahead=n This tuning parameter controls the maximum
181 number of inode table blocks that ext4's inode
182 table readahead algorithm will pre-read into
183 the buffer cache. The default value is 32 blocks.
184
174orlov (*) This enables the new Orlov block allocator. It is 185orlov (*) This enables the new Orlov block allocator. It is
175 enabled by default. 186 enabled by default.
176 187
@@ -212,6 +223,11 @@ errors=remount-ro(*) Remount the filesystem read-only on an error.
212errors=continue Keep going on a filesystem error. 223errors=continue Keep going on a filesystem error.
213errors=panic Panic and halt the machine if an error occurs. 224errors=panic Panic and halt the machine if an error occurs.
214 225
226data_err=ignore(*) Just print an error message if an error occurs
227 in a file data buffer in ordered mode.
228data_err=abort Abort the journal if an error occurs in a file
229 data buffer in ordered mode.
230
215grpid Give objects the same group ID as their creator. 231grpid Give objects the same group ID as their creator.
216bsdgroups 232bsdgroups
217 233
@@ -246,6 +262,7 @@ stripe=n Number of filesystem blocks that mballoc will try
246delalloc (*) Deferring block allocation until write-out time. 262delalloc (*) Deferring block allocation until write-out time.
247nodelalloc Disable delayed allocation. Blocks are allocation 263nodelalloc Disable delayed allocation. Blocks are allocation
248 when data is copied from user to page cache. 264 when data is copied from user to page cache.
265
249Data Mode 266Data Mode
250========= 267=========
251There are 3 different data modes: 268There are 3 different data modes: