diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/filesystems/ext4.txt | 20 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.txt | 39 |
2 files changed, 58 insertions, 1 deletions
diff --git a/Documentation/filesystems/ext4.txt b/Documentation/filesystems/ext4.txt index 6a4adcae9f9a..560f88dc7090 100644 --- a/Documentation/filesystems/ext4.txt +++ b/Documentation/filesystems/ext4.txt @@ -86,9 +86,21 @@ Alex is working on a new set of patches right now. When mounting an ext4 filesystem, the following option are accepted: (*) == default -extents ext4 will use extents to address file data. The +extents (*) ext4 will use extents to address file data. The file system will no longer be mountable by ext3. +noextents ext4 will not use extents for newly created files + +journal_checksum Enable checksumming of the journal transactions. + This will allow the recovery code in e2fsck and the + kernel to detect corruption in the kernel. It is a + compatible change and will be ignored by older kernels. + +journal_async_commit Commit block can be written to disk without waiting + for descriptor blocks. If enabled older kernels cannot + mount the device. This will enable 'journal_checksum' + internally. + journal=update Update the ext4 file system's journal to the current format. @@ -196,6 +208,12 @@ nobh (a) cache disk block mapping information "nobh" option tries to avoid associating buffer heads (supported only for "writeback" mode). +mballoc (*) Use the multiple block allocator for block allocation +nomballoc disabled multiple block allocator for block allocation. +stripe=n Number of filesystem blocks that mballoc will try + to use for allocation size and alignment. For RAID5/6 + systems this should be the number of data + disks * RAID chunk size in file system blocks. Data Mode --------- 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. The "procs_blocked" line gives the number of processes currently blocked, waiting for I/O to complete. +1.9 Ext4 file system parameters +------------------------------ +Ext4 file system have one directory per partition under /proc/fs/ext4/ +# ls /proc/fs/ext4/hdc/ +group_prealloc max_to_scan mb_groups mb_history min_to_scan order2_req +stats stream_req + +mb_groups: +This file gives the details of mutiblock allocator buddy cache of free blocks + +mb_history: +Multiblock allocation history. + +stats: +This file indicate whether the multiblock allocator should start collecting +statistics. The statistics are shown during unmount + +group_prealloc: +The multiblock allocator normalize the block allocation request to +group_prealloc filesystem blocks if we don't have strip value set. +The stripe value can be specified at mount time or during mke2fs. + +max_to_scan: +How long multiblock allocator can look for a best extent (in found extents) + +min_to_scan: +How long multiblock allocator must look for a best extent + +order2_req: +Multiblock allocator use 2^N search using buddies only for requests greater +than or equal to order2_req. The request size is specfied in file system +blocks. A value of 2 indicate only if the requests are greater than or equal +to 4 blocks. + +stream_req: +Files smaller than stream_req are served by the stream allocator, whose +purpose is to pack requests as close each to other as possible to +produce smooth I/O traffic. Avalue of 16 indicate that file smaller than 16 +filesystem block size will use group based preallocation. ------------------------------------------------------------------------------ Summary |