.TH EXT4 5 "@E2FSPROGS_MONTH@ @E2FSPROGS_YEAR@" "E2fsprogs version @E2FSPROGS_VERSION@"
historically been the default file system for many Linux distributions.
to handle mount requests for ext2 and ext3 file systems.
of e2fsprogs will not support file systems with this ext4 feature enabled.
This ext4 feature allows more than 65000 subdirectories per directory.
dm-crypt may provide much better security.
supported by ext2, ext3, and ext4.
entries. This feature is supported by ext2, ext3, and ext4.
.BR mke2fs " or " tune2fs.
file system which uses it.
kernels from mounting file systems that they could not understand.
available in the resize inode.
in the older quota design) to be hidden inodes.
the project ID of inode will be managed when the filesystem is mounted.
#4 for group quota) and set them in the superblock.
automatically when the filesystem is mounted.
contiguous blocks available for data files.
to create a file system without initializing all of the block groups.
to create the file system.
.SH "Mount options for ext2"
The `ext2' filesystem is the standard Linux filesystem.
l c r c c l.
No checking is done at mount time. This is the default. This is fast.
don't have to be supported if ext4 kernel driver is used for ext2 and ext3 filesystems.
Define the behavior when an error is encountered.
These options define what group id a newly created file gets.
if it is a directory itself.
to actually enable and manage the quota system.
kernels which only store and expect 16-bit values.
These options determine who can use the reserved blocks.
as superblock. This could be useful when the filesystem has been damaged.
block 32768 on a filesystem with 4\ k blocks, use "sb=131072".
.SH "Mount options for ext3"
in devnum, or via a path to the device.
lead to any number of problems.
Specifies the journaling mode for file data. Metadata is always journaled.
system prior to its metadata being committed to the journal.
filesystem after its metadata has been committed to the journal.
in files after a crash and journal recovery.
.BR barrier=0 " / " barrier=1 "
seconds. The default value is 5 seconds. Zero means default.
advantage that even after a crash no quota check is required.
.SH "Mount options for ext4"
are backwardly compatible with ext3 or ext2.
compatible change and will be ignored by older kernels.
enabled older kernels cannot mount the device.
This will enable 'journal_checksum' internally.
ext4's inode table readahead algorithm will pre-read into the buffer cache.
The value must be a power of 2. The default value is 32 blocks.
RAID chunk size in filesystem blocks.
takes to finish committing a transaction. Call this time the "commit time".
fast disks, at the cost of increasing latency.
used for I/O operations submitted by kjournald2 during a commit operation.
remounting a filesystem which is already mounted.
crashes before the delayed allocation blocks are forced to disk.
then be deferred until the next time the filesystem is mounted.
system performance while the filesystem's inode table is being initialized.
purposes and since it negatively affects the performance, it is off by default.
before buffer write and convert the extent to initialized after IO completes.
journaling and dioread_nolock option will be ignored with kernel warning.
Note that dioread_nolock code path is only used for extent-based files.
.BR a " - append only"
.BR A " - no atime updates"
.BR d " - no dump"
.BR D " - synchronous directory updates"
.BR i " - immutable"
.BR S " - synchronous updates"
.BR u " - undeletable"
.BR j " - data journaling"
.BR e " - extents format"
in particular the kernel versions in certain "enterprise distributions"