Bug #546: direct i/o does not work when offset is not page-aligned - Linux kernel client - Ceph

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Bug #546

closed

direct i/o does not work when offset is not page-aligned

Added by Henry Chang over 13 years ago. Updated over 13 years ago.

Status:

Resolved

Priority:

Urgent

Assignee:

Sage Weil

Category:

Target version:

v2.6.37

% Done:

Spent time:

3:00 h

Source:

Tags:

Backport:

Regression:

Severity:

Reviewed:

Affected Versions:

ceph-qa-suite:

Crash signature (v1):

Crash signature (v2):

Description

When opening file with O_DIRECT, seeking to offset 6656 and reading 512 bytes gets wrong data.
Below is a strace log reading file on local fs:

open("/tmp/benian.img", O_RDONLY|O_DIRECT) = 3
stat("/tmp/benian.img", {st_mode=S_IFREG|0644, st_size=7168, ...}) = 0
lseek(3, 0, SEEK_END)                   = 7168
lseek(3, 0, SEEK_CUR)                   = 7168
lseek(3, 6656, SEEK_SET)                = 6656
read(3, "conectix\0\0\0\2\0\1\0\0\0\0\0\0\0\0\2\0\24c\355\337tap\0"..., 512) = 512

Below is the strace log reading file on ceph:

open("/mnt/depot0/benian.img", O_RDONLY|O_DIRECT) = 3
stat("/mnt/depot0/benian.img", {st_mode=S_IFREG|0644, st_size=7168, ...}) = 0
lseek(3, 0, SEEK_END)                   = 7168
lseek(3, 0, SEEK_CUR)                   = 7168
lseek(3, 6656, SEEK_SET)                = 6656
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 512) = 512

Files

benian.img (7 KB) benian.img

Henry Chang, 11/04/2010 11:04 PM