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author | majianpeng <majianpeng@gmail.com> | 2013-08-06 16:20:38 +0800 |
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committer | Sage Weil <sage@inktank.com> | 2013-08-27 12:28:45 -0700 |
commit | 02ae66d8b229708fd94b764f6c17ead1c7741fcf (patch) | |
tree | 3cbb18d37ceb0eb74d8fac86f8da9fd0ef8199f1 | |
parent | e90757432361bb8b3ad3c3fd866324ed47875693 (diff) | |
download | op-kernel-dev-02ae66d8b229708fd94b764f6c17ead1c7741fcf.zip op-kernel-dev-02ae66d8b229708fd94b764f6c17ead1c7741fcf.tar.gz |
ceph: fix bugs about handling short-read for sync read mode.
cephfs . show_layout
>layyout.data_pool: 0
>layout.object_size: 4194304
>layout.stripe_unit: 4194304
>layout.stripe_count: 1
TestA:
>dd if=/dev/urandom of=test bs=1M count=2 oflag=direct
>dd if=/dev/urandom of=test bs=1M count=2 seek=4 oflag=direct
>dd if=test of=/dev/null bs=6M count=1 iflag=direct
The messages from func striped_read are:
ceph: file.c:350 : striped_read 0~6291456 (read 0) got 2097152 HITSTRIPE SHORT
ceph: file.c:350 : striped_read 2097152~4194304 (read 2097152) got 0 HITSTRIPE SHORT
ceph: file.c:381 : zero tail 4194304
ceph: file.c:390 : striped_read returns 6291456
The hole of file is from 2M--4M.But actualy it zero the last 4M include
the last 2M area which isn't a hole.
Using this patch, the messages are:
ceph: file.c:350 : striped_read 0~6291456 (read 0) got 2097152 HITSTRIPE SHORT
ceph: file.c:358 : zero gap 2097152 to 4194304
ceph: file.c:350 : striped_read 4194304~2097152 (read 4194304) got 2097152
ceph: file.c:384 : striped_read returns 6291456
TestB:
>echo majianpeng > test
>dd if=test of=/dev/null bs=2M count=1 iflag=direct
The messages are:
ceph: file.c:350 : striped_read 0~6291456 (read 0) got 11 HITSTRIPE SHORT
ceph: file.c:350 : striped_read 11~6291445 (read 11) got 0 HITSTRIPE SHORT
ceph: file.c:390 : striped_read returns 11
For this case,it did once more striped_read.It's no meaningless.
Using this patch, the message are:
ceph: file.c:350 : striped_read 0~6291456 (read 0) got 11 HITSTRIPE SHORT
ceph: file.c:384 : striped_read returns 11
Big thanks to Yan Zheng for the patch.
Reviewed-by: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Jianpeng Ma <majianpeng@gmail.com>
-rw-r--r-- | fs/ceph/file.c | 39 |
1 files changed, 16 insertions, 23 deletions
diff --git a/fs/ceph/file.c b/fs/ceph/file.c index d5e12f5..98b9035 100644 --- a/fs/ceph/file.c +++ b/fs/ceph/file.c @@ -350,44 +350,37 @@ more: dout("striped_read %llu~%llu (read %u) got %d%s%s\n", pos, left, read, ret, hit_stripe ? " HITSTRIPE" : "", was_short ? " SHORT" : ""); - if (ret > 0) { - int didpages = (page_align + ret) >> PAGE_CACHE_SHIFT; - - if (read < pos - off) { - dout(" zero gap %llu to %llu\n", off + read, pos); - ceph_zero_page_vector_range(page_align + read, - pos - off - read, pages); + if (ret >= 0) { + int didpages; + if (was_short && (pos + ret < inode->i_size)) { + u64 tmp = min(this_len - ret, + inode->i_size - pos - ret); + dout(" zero gap %llu to %llu\n", + pos + ret, pos + ret + tmp); + ceph_zero_page_vector_range(page_align + read + ret, + tmp, pages); + ret += tmp; } + + didpages = (page_align + ret) >> PAGE_CACHE_SHIFT; pos += ret; read = pos - off; left -= ret; page_pos += didpages; pages_left -= didpages; - /* hit stripe? */ - if (left && hit_stripe) + /* hit stripe and need continue*/ + if (left && hit_stripe && pos < inode->i_size) goto more; } - if (was_short) { + if (ret >= 0) { + ret = read; /* did we bounce off eof? */ if (pos + left > inode->i_size) *checkeof = 1; - - /* zero trailing bytes (inside i_size) */ - if (left > 0 && pos < inode->i_size) { - if (pos + left > inode->i_size) - left = inode->i_size - pos; - - dout("zero tail %llu\n", left); - ceph_zero_page_vector_range(page_align + read, left, - pages); - read += left; - } } - if (ret >= 0) - ret = read; dout("striped_read returns %d\n", ret); return ret; } |