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https://issues.apache.org/jira/browse/HADOOP-14457?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16026745#comment-16026745
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Aaron Fabbri edited comment on HADOOP-14457 at 5/26/17 7:54 PM:
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First, I'm happy testing authoritative mode w/ LocalMetadataStore exposed a
logic bug in the FS client. Very cool.
Yep [~mackrorysd] the main bug here seems to be that S3A does not report the
directories it implicitly creates to the metadatastore. We could change
MetadataStore to have implicit ancestor creation semantics like
{{FileSystem#create()}}, but I favor the current semantics, mostly because the
FS client already often has to enumerate ancestors (e.g. create and mkdir), and
doing it again inside MetadataStore seems wasteful (especially since these will
be network round trips, and it sometimes will not be necessary).
In your test code from JIRA description:
{noformat}
+ assertTrue("MetadataStore falsely reports authoritative empty list",
+ list.isEmpty() == Tristate.FALSE || !list.isAuthoritative());
{noformat}
The check of {{!list.isAuthoritative()}} is redundant. {{FALSE}} means we know
it is empty. If you look at {{DirListingMetadata.isEmpty()}} you'll see it is
already considered there.
In your patch:
{noformat}
+ List<Path> metadataStoreDirs = null;
+ if (hasMetadataStore()) {
+ metadataStoreDirs = new ArrayList<>();
+ }
+ Path parent = qualify(f.getParent());
+ while (!parent.isRoot()) {
+ DirectoryStatus directory = checkPathForDirectory(parent);
+ if(directory == DirectoryStatus.EXISTS_AND_IS_FILE) {
+ throw new FileAlreadyExistsException("Parent directory " + parent +
+ " already exists as a file");
+ } else if (directory == DirectoryStatus.DOES_NOT_EXIST ||
+ directory == DirectoryStatus.EXISTS_AND_IS_DIRECTORY_ON_S3_ONLY) {
+ if (metadataStoreDirs != null) {
+ metadataStoreDirs.add(parent);
+ }
+ } else if (directory ==
+ DirectoryStatus.EXISTS_AND_IS_DIRECTORY_ON_METADATASTORE) {
+ break;
+ }
+ parent = parent.getParent();
+ }
+ S3Guard.makeDirsOrdered(metadataStore, metadataStoreDirs, username, false);
{noformat}
I'm wondering, both here and in your recent mkdirs() change, if we cannot
simplify this and just use getFileStatus() instead of your
checkPathForDirectory()
was (Author: fabbri):
First, I'm happy testing authoritative mode w/ LocalMetadataStore exposed a
logic bug in the FS client. Very cool.
Yep [~mackrorysd] the main bug here seems to be that S3A does not report the
directories it implicitly creates to the metadatastore. We could change
MetadataStore to have implicit ancestor creation semantics like
{{FileSystem#create()}}, but I favor the current semantics, mostly because the
FS client already often has to enumerate ancestors (e.g. create and mkdir), and
doing it again inside MetadataStore seems wasteful (especially since these will
be network round trips, and it sometimes will not be necessary).
In your test code from JIRA description:
{quote}
+ assertTrue("MetadataStore falsely reports authoritative empty list",
+ list.isEmpty() == Tristate.FALSE || !list.isAuthoritative());
{quote}
The check of {{!list.isAuthoritative()}} is redundant. {{FALSE}} means we know
it is empty. If you look at {{DirListingMetadata.isEmpty()}} you'll see it is
already considered there.
In your patch:
{quote}
+ List<Path> metadataStoreDirs = null;
+ if (hasMetadataStore()) {
+ metadataStoreDirs = new ArrayList<>();
+ }
+ Path parent = qualify(f.getParent());
+ while (!parent.isRoot()) {
+ DirectoryStatus directory = checkPathForDirectory(parent);
+ if(directory == DirectoryStatus.EXISTS_AND_IS_FILE) {
+ throw new FileAlreadyExistsException("Parent directory " + parent +
+ " already exists as a file");
+ } else if (directory == DirectoryStatus.DOES_NOT_EXIST ||
+ directory == DirectoryStatus.EXISTS_AND_IS_DIRECTORY_ON_S3_ONLY) {
+ if (metadataStoreDirs != null) {
+ metadataStoreDirs.add(parent);
+ }
+ } else if (directory ==
+ DirectoryStatus.EXISTS_AND_IS_DIRECTORY_ON_METADATASTORE) {
+ break;
+ }
+ parent = parent.getParent();
+ }
+ S3Guard.makeDirsOrdered(metadataStore, metadataStoreDirs, username, false);
{quote}
I'm wondering, both here and in your recent mkdirs() change, if we cannot
simplify this and just use getFileStatus() instead of your
checkPathForDirectory()
> LocalMetadataStore falsely reports empty parent directory authoritatively
> -------------------------------------------------------------------------
>
> Key: HADOOP-14457
> URL: https://issues.apache.org/jira/browse/HADOOP-14457
> Project: Hadoop Common
> Issue Type: Sub-task
> Components: fs/s3
> Reporter: Sean Mackrory
> Attachments: HADOOP-14457-HADOOP-13345.001.patch
>
>
> Not a great test yet, but it at least reliably demonstrates the issue.
> LocalMetadataStore will sometimes erroneously report that a directory is
> empty with isAuthoritative = true when it *definitely* has children the
> metadatastore should know about. It doesn't appear to happen if the children
> are just directory. The fact that it's returning an empty listing is
> concerning, but the fact that it says it's authoritative *might* be a second
> bug.
> {code}
> diff --git
> a/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java
>
> b/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java
> index 78b3970..1821d19 100644
> ---
> a/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java
> +++
> b/hadoop-tools/hadoop-aws/src/main/java/org/apache/hadoop/fs/s3a/S3AFileSystem.java
> @@ -965,7 +965,7 @@ public boolean hasMetadataStore() {
> }
>
> @VisibleForTesting
> - MetadataStore getMetadataStore() {
> + public MetadataStore getMetadataStore() {
> return metadataStore;
> }
>
> diff --git
> a/hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/contract/s3a/ITestS3AContractRename.java
>
> b/hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/contract/s3a/ITestS3AContractRename.java
> index 4339649..881bdc9 100644
> ---
> a/hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/contract/s3a/ITestS3AContractRename.java
> +++
> b/hadoop-tools/hadoop-aws/src/test/java/org/apache/hadoop/fs/contract/s3a/ITestS3AContractRename.java
> @@ -23,6 +23,11 @@
> import org.apache.hadoop.fs.contract.AbstractFSContract;
> import org.apache.hadoop.fs.FileSystem;
> import org.apache.hadoop.fs.Path;
> +import org.apache.hadoop.fs.s3a.S3AFileSystem;
> +import org.apache.hadoop.fs.s3a.Tristate;
> +import org.apache.hadoop.fs.s3a.s3guard.DirListingMetadata;
> +import org.apache.hadoop.fs.s3a.s3guard.MetadataStore;
> +import org.junit.Test;
>
> import static org.apache.hadoop.fs.contract.ContractTestUtils.dataset;
> import static org.apache.hadoop.fs.contract.ContractTestUtils.writeDataset;
> @@ -72,4 +77,24 @@ public void testRenameDirIntoExistingDir() throws
> Throwable {
> boolean rename = fs.rename(srcDir, destDir);
> assertFalse("s3a doesn't support rename to non-empty directory", rename);
> }
> +
> + @Test
> + public void testMkdirPopulatesFileAncestors() throws Exception {
> + final FileSystem fs = getFileSystem();
> + final MetadataStore ms = ((S3AFileSystem) fs).getMetadataStore();
> + final Path parent = path("testMkdirPopulatesFileAncestors/source");
> + try {
> + fs.mkdirs(parent);
> + final Path nestedFile = new Path(parent, "dir1/dir2/dir3/file4");
> + byte[] srcDataset = dataset(256, 'a', 'z');
> + writeDataset(fs, nestedFile, srcDataset, srcDataset.length,
> + 1024, false);
> +
> + DirListingMetadata list = ms.listChildren(parent);
> + assertTrue("MetadataStore falsely reports authoritative empty list",
> + list.isEmpty() == Tristate.FALSE || !list.isAuthoritative());
> + } finally {
> + fs.delete(parent, true);
> + }
> + }
> }
> {code}
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