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HDFS-470. libhdfs should handle 0-length reads from FSInputStream correctly. Contributed by Colin Patrick McCabe

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git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/trunk@1361446 13f79535-47bb-0310-9956-ffa450edef68
This commit is contained in:
Eli Collins 2012-07-14 00:03:58 +00:00
parent dcf0ac7a8a
commit 8c2a2f909c
3 changed files with 16 additions and 4 deletions
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3
hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt
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@ -477,6 +477,9 @@ Branch-2 ( Unreleased changes )
HDFS-3639. JspHelper#getUGI should always verify the token if
security is enabled. (eli)
HDFS-470. libhdfs should handle 0-length reads from FSInputStream
correctly. (Colin Patrick McCabe via eli)
BREAKDOWN OF HDFS-3042 SUBTASKS
HDFS-2185. HDFS portion of ZK-based FailoverController (todd)

8
hadoop-hdfs-project/hadoop-hdfs/src/main/native/hdfs.c
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@ -878,11 +878,15 @@ static int handleReadResult(int success, jvalue jVal, jthrowable jExc,
noReadBytes = -1;
} else {
noReadBytes = jVal.i;
if (noReadBytes < 0) {
if (noReadBytes == 0) {
// 0 from Java means try again, which is EINTR here
errno = EINTR;
noReadBytes = -1;
} else if (noReadBytes < 0) {
// -1 from Java is EOF, which is 0 here
errno = 0;
noReadBytes = 0;
}
errno = 0;
}
return noReadBytes;

9
hadoop-hdfs-project/hadoop-hdfs/src/main/native/hdfs.h
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@ -311,8 +311,13 @@ extern "C" {
* @param file The file handle.
* @param buffer The buffer to copy read bytes into.
* @param length The length of the buffer.
* @return Returns the number of bytes actually read, possibly less
* than than length;-1 on error.
* @return On success, a positive number indicating how many bytes
* were read.
* On end-of-file, 0.
* On error, -1. Errno will be set to the error code.
* Just like the POSIX read function, hdfsRead will return -1
* and set errno to EINTR if data is temporarily unavailable,
* but we are not yet at the end of the file.
*/
tSize hdfsRead(hdfsFS fs, hdfsFile file, void* buffer, tSize length);