Examples with DFSClient org.apache.hadoop.hdfs.DFSClient used on opensource projects

Example 11 with DFSClient

use of org.apache.hadoop.hdfs.DFSClient in project hadoop by apache.

the class RpcProgramNfs3 method write.

@VisibleForTesting
WRITE3Response write(XDR xdr, Channel channel, int xid, SecurityHandler securityHandler, SocketAddress remoteAddress) {
    WRITE3Response response = new WRITE3Response(Nfs3Status.NFS3_OK);
    DFSClient dfsClient = clientCache.getDfsClient(securityHandler.getUser());
    if (dfsClient == null) {
        response.setStatus(Nfs3Status.NFS3ERR_SERVERFAULT);
        return response;
    }
    WRITE3Request request;
    try {
        request = WRITE3Request.deserialize(xdr);
    } catch (IOException e) {
        LOG.error("Invalid WRITE request");
        return new WRITE3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    long offset = request.getOffset();
    int count = request.getCount();
    WriteStableHow stableHow = request.getStableHow();
    byte[] data = request.getData().array();
    if (data.length < count) {
        LOG.error("Invalid argument, data size is less than count in request");
        return new WRITE3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    FileHandle handle = request.getHandle();
    if (LOG.isDebugEnabled()) {
        LOG.debug("NFS WRITE fileId: " + handle.getFileId() + " offset: " + offset + " length: " + count + " stableHow: " + stableHow.getValue() + " xid: " + xid + " client: " + remoteAddress);
    }
    Nfs3FileAttributes preOpAttr = null;
    try {
        preOpAttr = writeManager.getFileAttr(dfsClient, handle, iug);
        if (preOpAttr == null) {
            LOG.error("Can't get path for fileId: " + handle.getFileId());
            return new WRITE3Response(Nfs3Status.NFS3ERR_STALE);
        }
        if (!checkAccessPrivilege(remoteAddress, AccessPrivilege.READ_WRITE)) {
            return new WRITE3Response(Nfs3Status.NFS3ERR_ACCES, new WccData(Nfs3Utils.getWccAttr(preOpAttr), preOpAttr), 0, stableHow, Nfs3Constant.WRITE_COMMIT_VERF);
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug("requested offset=" + offset + " and current filesize=" + preOpAttr.getSize());
        }
        writeManager.handleWrite(dfsClient, request, channel, xid, preOpAttr);
    } catch (IOException e) {
        LOG.info("Error writing to fileId " + handle.getFileId() + " at offset " + offset + " and length " + data.length, e);
        // Try to return WccData
        Nfs3FileAttributes postOpAttr = null;
        try {
            postOpAttr = writeManager.getFileAttr(dfsClient, handle, iug);
        } catch (IOException e1) {
            LOG.info("Can't get postOpAttr for fileId: " + handle.getFileId(), e1);
        }
        WccAttr attr = preOpAttr == null ? null : Nfs3Utils.getWccAttr(preOpAttr);
        WccData fileWcc = new WccData(attr, postOpAttr);
        int status = mapErrorStatus(e);
        return new WRITE3Response(status, fileWcc, 0, request.getStableHow(), Nfs3Constant.WRITE_COMMIT_VERF);
    }
    return null;
}

Example 12 with DFSClient

use of org.apache.hadoop.hdfs.DFSClient in project hadoop by apache.

the class RpcProgramNfs3 method lookup.

@VisibleForTesting
LOOKUP3Response lookup(XDR xdr, SecurityHandler securityHandler, SocketAddress remoteAddress) {
    LOOKUP3Response response = new LOOKUP3Response(Nfs3Status.NFS3_OK);
    if (!checkAccessPrivilege(remoteAddress, AccessPrivilege.READ_ONLY)) {
        response.setStatus(Nfs3Status.NFS3ERR_ACCES);
        return response;
    }
    DFSClient dfsClient = clientCache.getDfsClient(securityHandler.getUser());
    if (dfsClient == null) {
        response.setStatus(Nfs3Status.NFS3ERR_SERVERFAULT);
        return response;
    }
    LOOKUP3Request request;
    try {
        request = LOOKUP3Request.deserialize(xdr);
    } catch (IOException e) {
        LOG.error("Invalid LOOKUP request");
        return new LOOKUP3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    FileHandle dirHandle = request.getHandle();
    String fileName = request.getName();
    if (LOG.isDebugEnabled()) {
        LOG.debug("NFS LOOKUP dir fileId: " + dirHandle.getFileId() + " name: " + fileName + " client: " + remoteAddress);
    }
    try {
        String dirFileIdPath = Nfs3Utils.getFileIdPath(dirHandle);
        Nfs3FileAttributes postOpObjAttr = writeManager.getFileAttr(dfsClient, dirHandle, fileName);
        if (postOpObjAttr == null) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("NFS LOOKUP fileId: " + dirHandle.getFileId() + " name: " + fileName + " does not exist");
            }
            Nfs3FileAttributes postOpDirAttr = Nfs3Utils.getFileAttr(dfsClient, dirFileIdPath, iug);
            return new LOOKUP3Response(Nfs3Status.NFS3ERR_NOENT, null, null, postOpDirAttr);
        }
        Nfs3FileAttributes postOpDirAttr = Nfs3Utils.getFileAttr(dfsClient, dirFileIdPath, iug);
        if (postOpDirAttr == null) {
            LOG.info("Can't get path for dir fileId: " + dirHandle.getFileId());
            return new LOOKUP3Response(Nfs3Status.NFS3ERR_STALE);
        }
        FileHandle fileHandle = new FileHandle(postOpObjAttr.getFileId());
        return new LOOKUP3Response(Nfs3Status.NFS3_OK, fileHandle, postOpObjAttr, postOpDirAttr);
    } catch (IOException e) {
        LOG.warn("Exception ", e);
        int status = mapErrorStatus(e);
        return new LOOKUP3Response(status);
    }
}

Example 13 with DFSClient

use of org.apache.hadoop.hdfs.DFSClient in project hadoop by apache.

the class RpcProgramNfs3 method readdir.

public READDIR3Response readdir(XDR xdr, SecurityHandler securityHandler, SocketAddress remoteAddress) {
    READDIR3Response response = new READDIR3Response(Nfs3Status.NFS3_OK);
    if (!checkAccessPrivilege(remoteAddress, AccessPrivilege.READ_ONLY)) {
        response.setStatus(Nfs3Status.NFS3ERR_ACCES);
        return response;
    }
    DFSClient dfsClient = clientCache.getDfsClient(securityHandler.getUser());
    if (dfsClient == null) {
        response.setStatus(Nfs3Status.NFS3ERR_SERVERFAULT);
        return response;
    }
    READDIR3Request request;
    try {
        request = READDIR3Request.deserialize(xdr);
    } catch (IOException e) {
        LOG.error("Invalid READDIR request");
        return new READDIR3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    FileHandle handle = request.getHandle();
    long cookie = request.getCookie();
    if (cookie < 0) {
        LOG.error("Invalid READDIR request, with negative cookie: " + cookie);
        return new READDIR3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    long count = request.getCount();
    if (count <= 0) {
        LOG.info("Nonpositive count in invalid READDIR request: " + count);
        return new READDIR3Response(Nfs3Status.NFS3_OK);
    }
    if (LOG.isDebugEnabled()) {
        LOG.debug("NFS READDIR fileId: " + handle.getFileId() + " cookie: " + cookie + " count: " + count + " client: " + remoteAddress);
    }
    HdfsFileStatus dirStatus;
    DirectoryListing dlisting;
    Nfs3FileAttributes postOpAttr;
    long dotdotFileId = 0;
    try {
        String dirFileIdPath = Nfs3Utils.getFileIdPath(handle);
        dirStatus = dfsClient.getFileInfo(dirFileIdPath);
        if (dirStatus == null) {
            LOG.info("Can't get path for fileId: " + handle.getFileId());
            return new READDIR3Response(Nfs3Status.NFS3ERR_STALE);
        }
        if (!dirStatus.isDir()) {
            LOG.error("Can't readdir for regular file, fileId: " + handle.getFileId());
            return new READDIR3Response(Nfs3Status.NFS3ERR_NOTDIR);
        }
        long cookieVerf = request.getCookieVerf();
        if ((cookieVerf != 0) && (cookieVerf != dirStatus.getModificationTime())) {
            if (aixCompatMode) {
                // The AIX NFS client misinterprets RFC-1813 and will repeatedly send
                // the same cookieverf value even across VFS-level readdir calls,
                // instead of getting a new cookieverf for every VFS-level readdir
                // call, and reusing the cookieverf only in the event that multiple
                // incremental NFS-level readdir calls must be made to fetch all of
                // the directory entries. This means that whenever a readdir call is
                // made by an AIX NFS client for a given directory, and that directory
                // is subsequently modified, thus changing its mtime, no later readdir
                // calls will succeed from AIX for that directory until the FS is
                // unmounted/remounted. See HDFS-6549 for more info.
                LOG.warn("AIX compatibility mode enabled, ignoring cookieverf " + "mismatches.");
            } else {
                LOG.error("CookieVerf mismatch. request cookieVerf: " + cookieVerf + " dir cookieVerf: " + dirStatus.getModificationTime());
                return new READDIR3Response(Nfs3Status.NFS3ERR_BAD_COOKIE, Nfs3Utils.getFileAttr(dfsClient, dirFileIdPath, iug));
            }
        }
        if (cookie == 0) {
            // Get dotdot fileId
            String dotdotFileIdPath = dirFileIdPath + "/..";
            HdfsFileStatus dotdotStatus = dfsClient.getFileInfo(dotdotFileIdPath);
            if (dotdotStatus == null) {
                // This should not happen
                throw new IOException("Can't get path for handle path: " + dotdotFileIdPath);
            }
            dotdotFileId = dotdotStatus.getFileId();
        }
        // Get the list from the resume point
        byte[] startAfter;
        if (cookie == 0) {
            startAfter = HdfsFileStatus.EMPTY_NAME;
        } else {
            String inodeIdPath = Nfs3Utils.getFileIdPath(cookie);
            startAfter = inodeIdPath.getBytes(Charset.forName("UTF-8"));
        }
        dlisting = listPaths(dfsClient, dirFileIdPath, startAfter);
        postOpAttr = Nfs3Utils.getFileAttr(dfsClient, dirFileIdPath, iug);
        if (postOpAttr == null) {
            LOG.error("Can't get path for fileId: " + handle.getFileId());
            return new READDIR3Response(Nfs3Status.NFS3ERR_STALE);
        }
    } catch (IOException e) {
        LOG.warn("Exception ", e);
        int status = mapErrorStatus(e);
        return new READDIR3Response(status);
    }
    /**
     * Set up the dirents in the response. fileId is used as the cookie with one
     * exception. Linux client can either be stuck with "ls" command (on REHL)
     * or report "Too many levels of symbolic links" (Ubuntu).
     *
     * The problem is that, only two items returned, "." and ".." when the
     * namespace is empty. Both of them are "/" with the same cookie(root
     * fileId). Linux client doesn't think such a directory is a real directory.
     * Even though NFS protocol specifies cookie is an opaque data, Linux client
     * somehow doesn't like an empty dir returns same cookie for both "." and
     * "..".
     *
     * The workaround is to use 0 as the cookie for "." and always return "." as
     * the first entry in readdir/readdirplus response.
     */
    HdfsFileStatus[] fstatus = dlisting.getPartialListing();
    int n = (int) Math.min(fstatus.length, count - 2);
    boolean eof = (n >= fstatus.length) && !dlisting.hasMore();
    Entry3[] entries;
    if (cookie == 0) {
        entries = new Entry3[n + 2];
        entries[0] = new READDIR3Response.Entry3(postOpAttr.getFileId(), ".", 0);
        entries[1] = new READDIR3Response.Entry3(dotdotFileId, "..", dotdotFileId);
        for (int i = 2; i < n + 2; i++) {
            entries[i] = new READDIR3Response.Entry3(fstatus[i - 2].getFileId(), fstatus[i - 2].getLocalName(), fstatus[i - 2].getFileId());
        }
    } else {
        // Resume from last readdirplus. If the cookie is "..", the result
        // list is up the directory content since HDFS uses name as resume point.    
        entries = new Entry3[n];
        for (int i = 0; i < n; i++) {
            entries[i] = new READDIR3Response.Entry3(fstatus[i].getFileId(), fstatus[i].getLocalName(), fstatus[i].getFileId());
        }
    }
    DirList3 dirList = new READDIR3Response.DirList3(entries, eof);
    return new READDIR3Response(Nfs3Status.NFS3_OK, postOpAttr, dirStatus.getModificationTime(), dirList);
}

Example 14 with DFSClient

use of org.apache.hadoop.hdfs.DFSClient in project hadoop by apache.

the class RpcProgramNfs3 method readdirplus.

@VisibleForTesting
READDIRPLUS3Response readdirplus(XDR xdr, SecurityHandler securityHandler, SocketAddress remoteAddress) {
    if (!checkAccessPrivilege(remoteAddress, AccessPrivilege.READ_ONLY)) {
        return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_ACCES);
    }
    DFSClient dfsClient = clientCache.getDfsClient(securityHandler.getUser());
    if (dfsClient == null) {
        return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_SERVERFAULT);
    }
    READDIRPLUS3Request request = null;
    try {
        request = READDIRPLUS3Request.deserialize(xdr);
    } catch (IOException e) {
        LOG.error("Invalid READDIRPLUS request");
        return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    FileHandle handle = request.getHandle();
    long cookie = request.getCookie();
    if (cookie < 0) {
        LOG.error("Invalid READDIRPLUS request, with negative cookie: " + cookie);
        return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    long dirCount = request.getDirCount();
    if (dirCount <= 0) {
        LOG.info("Nonpositive dircount in invalid READDIRPLUS request: " + dirCount);
        return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    int maxCount = request.getMaxCount();
    if (maxCount <= 0) {
        LOG.info("Nonpositive maxcount in invalid READDIRPLUS request: " + maxCount);
        return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    if (LOG.isDebugEnabled()) {
        LOG.debug("NFS READDIRPLUS fileId: " + handle.getFileId() + " cookie: " + cookie + " dirCount: " + dirCount + " maxCount: " + maxCount + " client: " + remoteAddress);
    }
    HdfsFileStatus dirStatus;
    DirectoryListing dlisting;
    Nfs3FileAttributes postOpDirAttr;
    long dotdotFileId = 0;
    HdfsFileStatus dotdotStatus = null;
    try {
        String dirFileIdPath = Nfs3Utils.getFileIdPath(handle);
        dirStatus = dfsClient.getFileInfo(dirFileIdPath);
        if (dirStatus == null) {
            LOG.info("Can't get path for fileId: " + handle.getFileId());
            return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_STALE);
        }
        if (!dirStatus.isDir()) {
            LOG.error("Can't readdirplus for regular file, fileId: " + handle.getFileId());
            return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_NOTDIR);
        }
        long cookieVerf = request.getCookieVerf();
        if ((cookieVerf != 0) && (cookieVerf != dirStatus.getModificationTime())) {
            if (aixCompatMode) {
                // The AIX NFS client misinterprets RFC-1813 and will repeatedly send
                // the same cookieverf value even across VFS-level readdir calls,
                // instead of getting a new cookieverf for every VFS-level readdir
                // call. This means that whenever a readdir call is made by an AIX NFS
                // client for a given directory, and that directory is subsequently
                // modified, thus changing its mtime, no later readdir calls will
                // succeed for that directory from AIX until the FS is
                // unmounted/remounted. See HDFS-6549 for more info.
                LOG.warn("AIX compatibility mode enabled, ignoring cookieverf " + "mismatches.");
            } else {
                LOG.error("cookieverf mismatch. request cookieverf: " + cookieVerf + " dir cookieverf: " + dirStatus.getModificationTime());
                return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_BAD_COOKIE, Nfs3Utils.getFileAttr(dfsClient, dirFileIdPath, iug), 0, null);
            }
        }
        if (cookie == 0) {
            // Get dotdot fileId
            String dotdotFileIdPath = dirFileIdPath + "/..";
            dotdotStatus = dfsClient.getFileInfo(dotdotFileIdPath);
            if (dotdotStatus == null) {
                // This should not happen
                throw new IOException("Can't get path for handle path: " + dotdotFileIdPath);
            }
            dotdotFileId = dotdotStatus.getFileId();
        }
        // Get the list from the resume point
        byte[] startAfter;
        if (cookie == 0) {
            startAfter = HdfsFileStatus.EMPTY_NAME;
        } else {
            String inodeIdPath = Nfs3Utils.getFileIdPath(cookie);
            startAfter = inodeIdPath.getBytes(Charset.forName("UTF-8"));
        }
        dlisting = listPaths(dfsClient, dirFileIdPath, startAfter);
        postOpDirAttr = Nfs3Utils.getFileAttr(dfsClient, dirFileIdPath, iug);
        if (postOpDirAttr == null) {
            LOG.info("Can't get path for fileId: " + handle.getFileId());
            return new READDIRPLUS3Response(Nfs3Status.NFS3ERR_STALE);
        }
    } catch (IOException e) {
        LOG.warn("Exception ", e);
        int status = mapErrorStatus(e);
        return new READDIRPLUS3Response(status);
    }
    // Set up the dirents in the response
    HdfsFileStatus[] fstatus = dlisting.getPartialListing();
    int n = (int) Math.min(fstatus.length, dirCount - 2);
    boolean eof = (n >= fstatus.length) && !dlisting.hasMore();
    READDIRPLUS3Response.EntryPlus3[] entries;
    if (cookie == 0) {
        entries = new READDIRPLUS3Response.EntryPlus3[n + 2];
        entries[0] = new READDIRPLUS3Response.EntryPlus3(postOpDirAttr.getFileId(), ".", 0, postOpDirAttr, new FileHandle(postOpDirAttr.getFileId()));
        entries[1] = new READDIRPLUS3Response.EntryPlus3(dotdotFileId, "..", dotdotFileId, Nfs3Utils.getNfs3FileAttrFromFileStatus(dotdotStatus, iug), new FileHandle(dotdotFileId));
        for (int i = 2; i < n + 2; i++) {
            long fileId = fstatus[i - 2].getFileId();
            FileHandle childHandle = new FileHandle(fileId);
            Nfs3FileAttributes attr;
            try {
                attr = writeManager.getFileAttr(dfsClient, childHandle, iug);
            } catch (IOException e) {
                LOG.error("Can't get file attributes for fileId: " + fileId, e);
                continue;
            }
            entries[i] = new READDIRPLUS3Response.EntryPlus3(fileId, fstatus[i - 2].getLocalName(), fileId, attr, childHandle);
        }
    } else {
        // Resume from last readdirplus. If the cookie is "..", the result
        // list is up the directory content since HDFS uses name as resume point.
        entries = new READDIRPLUS3Response.EntryPlus3[n];
        for (int i = 0; i < n; i++) {
            long fileId = fstatus[i].getFileId();
            FileHandle childHandle = new FileHandle(fileId);
            Nfs3FileAttributes attr;
            try {
                attr = writeManager.getFileAttr(dfsClient, childHandle, iug);
            } catch (IOException e) {
                LOG.error("Can't get file attributes for fileId: " + fileId, e);
                continue;
            }
            entries[i] = new READDIRPLUS3Response.EntryPlus3(fileId, fstatus[i].getLocalName(), fileId, attr, childHandle);
        }
    }
    DirListPlus3 dirListPlus = new READDIRPLUS3Response.DirListPlus3(entries, eof);
    return new READDIRPLUS3Response(Nfs3Status.NFS3_OK, postOpDirAttr, dirStatus.getModificationTime(), dirListPlus);
}

Example 15 with DFSClient

use of org.apache.hadoop.hdfs.DFSClient in project hadoop by apache.

the class RpcProgramNfs3 method read.

@VisibleForTesting
READ3Response read(XDR xdr, SecurityHandler securityHandler, SocketAddress remoteAddress) {
    READ3Response response = new READ3Response(Nfs3Status.NFS3_OK);
    final String userName = securityHandler.getUser();
    if (!checkAccessPrivilege(remoteAddress, AccessPrivilege.READ_ONLY)) {
        response.setStatus(Nfs3Status.NFS3ERR_ACCES);
        return response;
    }
    DFSClient dfsClient = clientCache.getDfsClient(userName);
    if (dfsClient == null) {
        response.setStatus(Nfs3Status.NFS3ERR_SERVERFAULT);
        return response;
    }
    READ3Request request;
    try {
        request = READ3Request.deserialize(xdr);
    } catch (IOException e) {
        LOG.error("Invalid READ request");
        return new READ3Response(Nfs3Status.NFS3ERR_INVAL);
    }
    long offset = request.getOffset();
    int count = request.getCount();
    FileHandle handle = request.getHandle();
    if (LOG.isDebugEnabled()) {
        LOG.debug("NFS READ fileId: " + handle.getFileId() + " offset: " + offset + " count: " + count + " client: " + remoteAddress);
    }
    Nfs3FileAttributes attrs;
    boolean eof;
    if (count == 0) {
        // Only do access check.
        try {
            // Don't read from cache. Client may not have read permission.
            attrs = Nfs3Utils.getFileAttr(dfsClient, Nfs3Utils.getFileIdPath(handle), iug);
        } catch (IOException e) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Get error accessing file, fileId: " + handle.getFileId(), e);
            }
            return new READ3Response(Nfs3Status.NFS3ERR_IO);
        }
        if (attrs == null) {
            if (LOG.isDebugEnabled()) {
                LOG.debug("Can't get path for fileId: " + handle.getFileId());
            }
            return new READ3Response(Nfs3Status.NFS3ERR_NOENT);
        }
        int access = Nfs3Utils.getAccessRightsForUserGroup(securityHandler.getUid(), securityHandler.getGid(), securityHandler.getAuxGids(), attrs);
        if ((access & Nfs3Constant.ACCESS3_READ) != 0) {
            eof = offset >= attrs.getSize();
            return new READ3Response(Nfs3Status.NFS3_OK, attrs, 0, eof, ByteBuffer.wrap(new byte[0]));
        } else {
            return new READ3Response(Nfs3Status.NFS3ERR_ACCES);
        }
    }
    // In case there is buffered data for the same file, flush it. This can be
    // optimized later by reading from the cache.
    int ret = writeManager.commitBeforeRead(dfsClient, handle, offset + count);
    if (ret != Nfs3Status.NFS3_OK) {
        LOG.warn("commitBeforeRead didn't succeed with ret=" + ret + ". Read may not get most recent data.");
    }
    try {
        int rtmax = config.getInt(NfsConfigKeys.DFS_NFS_MAX_READ_TRANSFER_SIZE_KEY, NfsConfigKeys.DFS_NFS_MAX_READ_TRANSFER_SIZE_DEFAULT);
        int buffSize = Math.min(rtmax, count);
        byte[] readbuffer = new byte[buffSize];
        int readCount = 0;
        /**
       * Retry exactly once because the DFSInputStream can be stale.
       */
        for (int i = 0; i < 1; ++i) {
            FSDataInputStream fis = clientCache.getDfsInputStream(userName, Nfs3Utils.getFileIdPath(handle));
            if (fis == null) {
                return new READ3Response(Nfs3Status.NFS3ERR_ACCES);
            }
            try {
                readCount = fis.read(offset, readbuffer, 0, count);
                metrics.incrBytesRead(readCount);
            } catch (IOException e) {
                // which requires incompatible changes.
                if (e.getMessage().equals("Stream closed")) {
                    clientCache.invalidateDfsInputStream(userName, Nfs3Utils.getFileIdPath(handle));
                    continue;
                } else {
                    throw e;
                }
            }
        }
        attrs = Nfs3Utils.getFileAttr(dfsClient, Nfs3Utils.getFileIdPath(handle), iug);
        if (readCount < count) {
            LOG.info("Partial read. Asked offset: " + offset + " count: " + count + " and read back: " + readCount + " file size: " + attrs.getSize());
        }
        // HDFS returns -1 for read beyond file size.
        if (readCount < 0) {
            readCount = 0;
        }
        eof = (offset + readCount) >= attrs.getSize();
        return new READ3Response(Nfs3Status.NFS3_OK, attrs, readCount, eof, ByteBuffer.wrap(readbuffer));
    } catch (IOException e) {
        LOG.warn("Read error: " + e.getClass() + " offset: " + offset + " count: " + count, e);
        int status = mapErrorStatus(e);
        return new READ3Response(status);
    }
}