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authormajianpeng <majianpeng@gmail.com>2013-08-06 16:20:38 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-09 12:24:25 -0800
commit533bc2950e085ee99225655f60276760c00af31f (patch)
tree5ce118050f15063624b69a4bfe362eb20edf50fa /fs
parent3834fb30d260b8fa6401fff271c65cd29ba94424 (diff)
downloadlinaro-lsk-533bc2950e085ee99225655f60276760c00af31f.tar.gz
ceph: fix bugs about handling short-read for sync read mode.
commit 02ae66d8b229708fd94b764f6c17ead1c7741fcf upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/ceph/file.c39
1 files changed, 16 insertions, 23 deletions
diff --git a/fs/ceph/file.c b/fs/ceph/file.c
index 5b9baf5a867..1ac0a59867d 100644
--- a/fs/ceph/file.c
+++ b/fs/ceph/file.c
@@ -349,44 +349,37 @@ 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;
}