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path: root/fs/ext4/ialloc.c
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2007-10-17Ext4: Uninitialized Block GroupsAndreas Dilger
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 <mathur@us.ibm.com> Signed-off-by: Andreas Dilger <adilger@clusterfs.com> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
2007-10-17ext4: Remove (partial, never completed) fragment supportColy Li
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 <coyli@suse.de> Acked-by: Andreas Dilger <adilger@clusterfs.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2007-10-17remove unused bh in calls to ext234_get_group_descEric Sandeen
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 <sandeen@redhat.com> Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-18ext4: Add nanosecond timestampsKalpak Shah
This patch adds nanosecond timestamps for ext4. This involves adding *time_extra fields to the ext4_inode to extend the timestamps to 64-bits. Creation time is also added by this patch. These extended fields will fit into an inode if the filesystem was formatted with large inodes (-I 256 or larger) and there are currently no EAs consuming all of the available space. For new inodes we always reserve enough space for the kernel's known extended fields, but for inodes created with an old kernel this might not have been the case. So this patch also adds the EXT4_FEATURE_RO_COMPAT_EXTRA_ISIZE feature flag(ro-compat so that older kernels can't create inodes with a smaller extra_isize). which indicates if the fields fitting inside s_min_extra_isize are available or not. If the expansion of inodes if unsuccessful then this feature will be disabled. This feature is only enabled if requested by the sysadmin. None of the extended inode fields is critical for correct filesystem operation. Signed-off-by: Andreas Dilger <adilger@clusterfs.com> Signed-off-by: Kalpak Shah <kalpak@clusterfs.com> Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2006-10-11[PATCH] ext4 64 bit divide fixAndrew Morton
With CONFIG_LBD=n, sector_div() expands to a plain old divide. But ext4 is _not_ passing in a sector_t as the first argument, so... fs/built-in.o: In function `ext4_get_group_no_and_offset': fs/ext4/balloc.c:39: undefined reference to `__umoddi3' fs/ext4/balloc.c:41: undefined reference to `__udivdi3' fs/built-in.o: In function `find_group_orlov': fs/ext4/ialloc.c:278: undefined reference to `__udivdi3' fs/built-in.o: In function `ext4_fill_super': fs/ext4/super.c:1488: undefined reference to `__udivdi3' fs/ext4/super.c:1488: undefined reference to `__umoddi3' fs/ext4/super.c:1594: undefined reference to `__udivdi3' fs/ext4/super.c:1601: undefined reference to `__umoddi3' Fix that up by calling do_div() directly. Also cast the arg to u64. do_div() is only defined on u64, and ext4_fsblk_t is supposed to be opaque. Note especially the changes to find_group_orlov(). It was attempting to do do_div(int, unsigned long long); which is royally screwed up. Switched it to plain old divide. Cc: <linux-ext4@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] ext4: move block number hi bitsAlexandre Ratchov
move '_hi' bits of block numbers in the larger part of the block group descriptor structure Signed-off-by: Alexandre Ratchov <alexandre.ratchov@bull.net> Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] ext4: 64bit metadataLaurent Vivier
In-kernel super block changes to support >32 bit free blocks numbers. Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net> Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Alexandre Ratchov <alexandre.ratchov@bull.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] ext4: switch fsblk to sector_tMingming Cao
Redefine ext3 in-kernel filesystem block type (ext3_fsblk_t) from unsigned long to sector_t, to allow kernel to handle >32 bit ext3 blocks. Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] ext3: add extent map supportAlex Tomas
On disk extents format: /* * this is extent on-disk structure * it's used at the bottom of the tree */ struct ext3_extent { __le32 ee_block; /* first logical block extent covers */ __le16 ee_len; /* number of blocks covered by extent */ __le16 ee_start_hi; /* high 16 bits of physical block */ __le32 ee_start; /* low 32 bigs of physical block */ }; Signed-off-by: Alex Tomas <alex@clusterfs.com> Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] jbd2: enable building of jbd2 and have ext4 use it rather than jbdMingming Cao
Reworked from a patch by Mingming Cao and Randy Dunlap Signed-off-By: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] ext4: rename ext4 symbols to avoid duplication of ext3 symbolsMingming Cao
Mingming Cao originally did this work, and Shaggy reproduced it using some scripts from her. Signed-off-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11[PATCH] ext4: initial copy of files from ext3Dave Kleikamp
Start of the ext4 patch series. See Documentation/filesystems/ext4.txt for details. This is a simple copy of the files in fs/ext3 to fs/ext4 and /usr/incude/linux/ext3* to /usr/include/ex4* Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>