aboutsummaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/ext4.txt10
-rw-r--r--Documentation/filesystems/proc.txt39
2 files changed, 48 insertions, 1 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt
index 4f329afe20ec..560f88dc7090 100644
--- a/Documentation/filesystems/ext4.txt
+++ b/Documentation/filesystems/ext4.txt
@@ -86,9 +86,11 @@ Alex is working on a new set of patches right now.
86When mounting an ext4 filesystem, the following option are accepted: 86When mounting an ext4 filesystem, the following option are accepted:
87(*) == default 87(*) == default
88 88
89extents ext4 will use extents to address file data. The 89extents (*) ext4 will use extents to address file data. The
90 file system will no longer be mountable by ext3. 90 file system will no longer be mountable by ext3.
91 91
92noextents ext4 will not use extents for newly created files
93
92journal_checksum Enable checksumming of the journal transactions. 94journal_checksum Enable checksumming of the journal transactions.
93 This will allow the recovery code in e2fsck and the 95 This will allow the recovery code in e2fsck and the
94 kernel to detect corruption in the kernel. It is a 96 kernel to detect corruption in the kernel. It is a
@@ -206,6 +208,12 @@ nobh (a) cache disk block mapping information
206 "nobh" option tries to avoid associating buffer 208 "nobh" option tries to avoid associating buffer
207 heads (supported only for "writeback" mode). 209 heads (supported only for "writeback" mode).
208 210
211mballoc (*) Use the multiple block allocator for block allocation
212nomballoc disabled multiple block allocator for block allocation.
213stripe=n Number of filesystem blocks that mballoc will try
214 to use for allocation size and alignment. For RAID5/6
215 systems this should be the number of data
216 disks * RAID chunk size in file system blocks.
209 217
210Data Mode 218Data Mode
211--------- 219---------
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index dec99455321f..4413a2d4646f 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -857,6 +857,45 @@ CPUs.
857The "procs_blocked" line gives the number of processes currently blocked, 857The "procs_blocked" line gives the number of processes currently blocked,
858waiting for I/O to complete. 858waiting for I/O to complete.
859 859
8601.9 Ext4 file system parameters
861------------------------------
862Ext4 file system have one directory per partition under /proc/fs/ext4/
863# ls /proc/fs/ext4/hdc/
864group_prealloc max_to_scan mb_groups mb_history min_to_scan order2_req
865stats stream_req
866
867mb_groups:
868This file gives the details of mutiblock allocator buddy cache of free blocks
869
870mb_history:
871Multiblock allocation history.
872
873stats:
874This file indicate whether the multiblock allocator should start collecting
875statistics. The statistics are shown during unmount
876
877group_prealloc:
878The multiblock allocator normalize the block allocation request to
879group_prealloc filesystem blocks if we don't have strip value set.
880The stripe value can be specified at mount time or during mke2fs.
881
882max_to_scan:
883How long multiblock allocator can look for a best extent (in found extents)
884
885min_to_scan:
886How long multiblock allocator must look for a best extent
887
888order2_req:
889Multiblock allocator use 2^N search using buddies only for requests greater
890than or equal to order2_req. The request size is specfied in file system
891blocks. A value of 2 indicate only if the requests are greater than or equal
892to 4 blocks.
893
894stream_req:
895Files smaller than stream_req are served by the stream allocator, whose
896purpose is to pack requests as close each to other as possible to
897produce smooth I/O traffic. Avalue of 16 indicate that file smaller than 16
898filesystem block size will use group based preallocation.
860 899
861------------------------------------------------------------------------------ 900------------------------------------------------------------------------------
862Summary 901Summary