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ext4_ext_find_goal() returns an ideal physical block number that the block allocator tries to allocate first. However, if a required file offset is smaller than the existing extent's one, ext4_ext_find_goal() returns a wrong block number because it may overflow at "block - le32_to_cpu(ex->ee_block)". This patch fixes the problem. ext4_ext_find_goal() will also return a wrong block number in case a file offset of the existing extent is too big. In this case, the ideal physical block number is fixed in ext4_mb_initialize_context(), so it's no problem. reproduce: # dd if=/dev/zero of=/mnt/mp1/tmp bs=127M count=1 oflag=sync # dd if=/dev/zero of=/mnt/mp1/file bs=512K count=1 seek=1 oflag=sync # filefrag -v /mnt/mp1/file Filesystem type is: ef53 File size of /mnt/mp1/file is 1048576 (256 blocks, blocksize 4096) ext logical physical expected length flags 0 128 67456 128 eof /mnt/mp1/file: 2 extents found # rm -rf /mnt/mp1/tmp # echo $((512*4096)) > /sys/fs/ext4/loop0/mb_stream_req # dd if=/dev/zero of=/mnt/mp1/file bs=512K count=1 oflag=sync conv=notrunc result (linux-2.6.37-rc2 + ext4 patch queue): # filefrag -v /mnt/mp1/file Filesystem type is: ef53 File size of /mnt/mp1/file is 1048576 (256 blocks, blocksize 4096) ext logical physical expected length flags 0 0 33280 128 1 128 67456 33407 128 eof /mnt/mp1/file: 2 extents found result(apply this patch): # filefrag -v /mnt/mp1/file Filesystem type is: ef53 File size of /mnt/mp1/file is 1048576 (256 blocks, blocksize 4096) ext logical physical expected length flags 0 0 66560 128 1 128 67456 66687 128 eof /mnt/mp1/file: 2 extents found Signed-off-by: Kazuya Mio <k-mio@sx.jp.nec.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> |
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| .. | ||
| acl.c | ||
| acl.h | ||
| balloc.c | ||
| bitmap.c | ||
| block_validity.c | ||
| dir.c | ||
| ext4.h | ||
| ext4_extents.h | ||
| ext4_jbd2.c | ||
| ext4_jbd2.h | ||
| extents.c | ||
| file.c | ||
| fsync.c | ||
| hash.c | ||
| ialloc.c | ||
| inode.c | ||
| ioctl.c | ||
| Kconfig | ||
| Makefile | ||
| mballoc.c | ||
| mballoc.h | ||
| migrate.c | ||
| move_extent.c | ||
| namei.c | ||
| page-io.c | ||
| resize.c | ||
| super.c | ||
| symlink.c | ||
| xattr.c | ||
| xattr.h | ||
| xattr_security.c | ||
| xattr_trusted.c | ||
| xattr_user.c | ||