linux-toradex.git/fs/ext4/ialloc.c, branch v2.6.25.12

ext4: set EXT4_EXTENTS_FL only for directory and regular files

2008-02-25T21:38:03+00:00

In addition, don't inherit EXT4_EXTENTS_FL from parent directory.
If we have a directory with extent flag set and later mount the file
system with -o noextents, the files created in that directory will also
have extent flag set but we would not have called ext4_ext_tree_init for
them. This will cause error later when we are verifying the extent header

Signed-off-by: Aneesh Kumar K.V 
Acked-off-by: Eric Sandeen 
Signed-off-by: Mingming Cao 
Signed-off-by: "Theodore Ts'o"

iget: stop EXT4 from using iget() and read_inode()

2008-02-07T16:42:27+00:00

Stop the EXT4 filesystem from using iget() and read_inode().  Replace
ext4_read_inode() with ext4_iget(), and call that instead of iget().
ext4_iget() then uses iget_locked() directly and returns a proper error code
instead of an inode in the event of an error.

ext4_fill_super() returns any error incurred when getting the root inode
instead of EINVAL.

Signed-off-by: David Howells 
Acked-by: "Theodore Ts'o" 
Acked-by: Jan Kara 
Cc: 
Acked-by: Christoph Hellwig 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

ext4: fix up EXT4FS_DEBUG builds

2008-01-29T04:58:27+00:00

Builds with EXT4FS_DEBUG defined (to enable ext4_debug()) fail
without these changes.  Clean up some format warnings too.

Signed-off-by: Eric Sandeen 
Signed-off-by: Mingming Cao

ext4: Rename i_dir_acl to i_size_high

2008-01-29T04:58:27+00:00

Rename ext4_inode.i_dir_acl to i_size_high
drop ext4_inode_info.i_dir_acl as it is not used
Rename ext4_inode.i_size to ext4_inode.i_size_lo
Add helper function for accessing the ext4_inode combined i_size.

Signed-off-by: Aneesh Kumar K.V

ext4: Introduce ext4_update_*_feature

2008-01-29T04:58:27+00:00

Introduce ext4_update_*_feature and use them instead
of opencoding.


Signed-off-by: Aneesh Kumar K.V

ext4: fixes block group number being set to a negative value

2008-01-29T04:58:27+00:00

This patch fixes various places where the group number is set to a negative
value.

Signed-off-by: Avantika Mathur 
Signed-off-by: "Theodore Ts'o"

ext4: add ext4_group_t, and change all group variables to this type.

2008-01-29T04:58:27+00:00

In many places variables for block group are of type int, which limits the
maximum number of block groups to 2^31.  Each block group can have up to
2^15 blocks, with a 4K block size,  and the max filesystem size is limited to
2^31 * (2^15 * 2^12) = 2^58  -- or 256 PB

This patch introduces a new type ext4_group_t, of type unsigned long, to
represent block group numbers in ext4.
All occurrences of block group variables are converted to type ext4_group_t.

Signed-off-by: Avantika Mathur

Ext4: Uninitialized Block Groups

2007-10-17T22:50:00+00:00

In pass1 of e2fsck, every inode table in the fileystem is scanned and checked,
regardless of whether it is in use.  This is this the most time consuming part
of the filesystem check.  The unintialized block group feature can greatly
reduce e2fsck time by eliminating checking of uninitialized inodes.

With this feature, there is a a high water mark of used inodes for each block
group.  Block and inode bitmaps can be uninitialized on disk via a flag in the
group descriptor to avoid reading or scanning them at e2fsck time.  A checksum
of each group descriptor is used to ensure that corruption in the group
descriptor's bit flags does not cause incorrect operation.

The feature is enabled through a mkfs option

	mke2fs /dev/ -O uninit_groups

A patch adding support for uninitialized block groups to e2fsprogs tools has
been posted to the linux-ext4 mailing list.

The patches have been stress tested with fsstress and fsx.  In performance
tests testing e2fsck time, we have seen that e2fsck time on ext3 grows
linearly with the total number of inodes in the filesytem.  In ext4 with the
uninitialized block groups feature, the e2fsck time is constant, based
solely on the number of used inodes rather than the total inode count.
Since typical ext4 filesystems only use 1-10% of their inodes, this feature can
greatly reduce e2fsck time for users.  With performance improvement of 2-20
times, depending on how full the filesystem is.

The attached graph shows the major improvements in e2fsck times in filesystems
with a large total inode count, but few inodes in use.

In each group descriptor if we have

EXT4_BG_INODE_UNINIT set in bg_flags:
        Inode table is not initialized/used in this group. So we can skip
        the consistency check during fsck.
EXT4_BG_BLOCK_UNINIT set in bg_flags:
        No block in the group is used. So we can skip the block bitmap
        verification for this group.

We also add two new fields to group descriptor as a part of
uninitialized group patch.

        __le16  bg_itable_unused;       /* Unused inodes count */
        __le16  bg_checksum;            /* crc16(sb_uuid+group+desc) */

bg_itable_unused:

If we have EXT4_BG_INODE_UNINIT not set in bg_flags
then bg_itable_unused will give the offset within
the inode table till the inodes are used. This can be
used by fsck to skip list of inodes that are marked unused.

bg_checksum:
Now that we depend on bg_flags and bg_itable_unused to determine
the block and inode usage, we need to make sure group descriptor
is not corrupt. We add checksum to group descriptor to
detect corruption. If the descriptor is found to be corrupt, we
mark all the blocks and inodes in the group used.

Signed-off-by: Avantika Mathur 
Signed-off-by: Andreas Dilger 
Signed-off-by: Mingming Cao 
Signed-off-by: Aneesh Kumar K.V

ext4: Remove (partial, never completed) fragment support

2007-10-17T22:49:59+00:00

Fragment support in ext2/3/4 was never implemented, and it probably will
never be implemented.   So remove it from ext4.

Signed-off-by: Coly Li 
Acked-by: Andreas Dilger 
Signed-off-by: Andrew Morton 
Signed-off-by: "Theodore Ts'o"

remove unused bh in calls to ext234_get_group_desc

2007-10-17T15:42:49+00:00

ext[234]_get_group_desc never tests the bh argument, and only sets it if it
is passed in; it is perfectly happy with a NULL bh argument.  But, many
callers send one in and never use it.  May as well call with NULL like
other callers who don't use the bh.

Signed-off-by: Eric Sandeen 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds