LU-13397 lfs: mirror extend/copy keeps sparseness

[fs/lustre-release.git] / lustre / utils / liblustreapi_mirror.c

diff --git a/lustre/utils/liblustreapi_mirror.c b/lustre/utils/liblustreapi_mirror.c
index 464b9fb..a67629d 100644 (file)
--- a/lustre/utils/liblustreapi_mirror.c
+++ b/lustre/utils/liblustreapi_mirror.c
@@ -147,8 +147,8 @@ ssize_t llapi_mirror_read(int fd, unsigned int id, void *buf, size_t count,
        return result;
 }
 
-static ssize_t llapi_mirror_write(int fd, unsigned int id,
-                                  const void *buf, size_t count, off_t pos)
+ssize_t llapi_mirror_write(int fd, unsigned int id, const void *buf,
+                          size_t count, off_t pos)
 {
        size_t page_size = sysconf(_SC_PAGESIZE);
        ssize_t result = 0;
@@ -186,7 +186,7 @@ static ssize_t llapi_mirror_write(int fd, unsigned int id,
        return result;
 }
 
-static int llapi_mirror_truncate(int fd, unsigned int id, off_t length)
+int llapi_mirror_truncate(int fd, unsigned int id, off_t length)
 {
        int rc;
 
@@ -203,6 +203,48 @@ static int llapi_mirror_truncate(int fd, unsigned int id, off_t length)
        return rc;
 }
 
+bool llapi_mirror_is_sparse(int fd, unsigned int id)
+{
+       bool sparse;
+       int rc;
+
+       rc = llapi_mirror_set(fd, id);
+       if (rc < 0)
+               return false;
+
+       sparse = llapi_file_is_sparse(fd);
+       (void) llapi_mirror_clear(fd);
+
+       return sparse;
+}
+
+/**
+ * Seek data in a specified mirror with @id. This function looks for the
+ * first data segment from given offset and returns its offset and length
+ *
+ * \param fd   file descriptor, should be opened with O_DIRECT
+ * \param id   mirror id to be read from
+ * \param pos  position for start data seek from
+ * \param size size of data segment found
+ *
+ * \result >= 0        Number of bytes has been read
+ * \result < 0 The last seen error
+ */
+off_t llapi_mirror_data_seek(int fd, unsigned int id, off_t pos, size_t *size)
+{
+       off_t data_off;
+       int rc;
+
+       rc = llapi_mirror_set(fd, id);
+       if (rc < 0)
+               return rc;
+
+       data_off = llapi_data_seek(fd, pos, size);
+       (void) llapi_mirror_clear(fd);
+
+       return data_off;
+}
+
 /**
  * Copy data contents from source mirror @src to multiple destinations
  * pointed by @dst. The destination array @dst will be altered to store
@@ -216,15 +258,16 @@ static int llapi_mirror_truncate(int fd, unsigned int id, off_t length)
  * \result > 0 Number of mirrors successfully copied
  * \result < 0 The last seen error
  */
-ssize_t llapi_mirror_copy_many(int fd, unsigned int src, unsigned int *dst,
-                               size_t count)
+ssize_t llapi_mirror_copy_many(int fd, __u16 src, __u16 *dst, size_t count)
 {
        const size_t buflen = 4 * 1024 * 1024; /* 4M */
        void *buf;
-       loff_t pos = 0;
+       off_t pos = 0;
+       off_t data_end = 0;
        size_t page_size = sysconf(_SC_PAGESIZE);
        ssize_t result = 0;
        bool eof = false;
+       bool sparse;
        int nr;
        int i;
        int rc;
@@ -236,12 +279,61 @@ ssize_t llapi_mirror_copy_many(int fd, unsigned int src, unsigned int *dst,
        if (rc) /* error code is returned directly */
                return -rc;
 
+       sparse = llapi_mirror_is_sparse(fd, src);
+
        nr = count;
+       if (sparse) {
+               /* for sparse src we have to be sure that dst has no
+                * data in src holes, so truncate it first
+                */
+               for (i = 0; i < nr; i++) {
+                       rc = llapi_mirror_truncate(fd, dst[i], pos);
+                       if (rc < 0) {
+                               result = rc;
+                               /* exclude the failed one */
+                               dst[i] = dst[--nr];
+                               i--;
+                               continue;
+                       }
+               }
+               if (!nr)
+                       return result;
+       }
+
        while (!eof) {
+               off_t data_off;
                ssize_t bytes_read;
-               size_t to_write;
+               size_t to_write, to_read;
+
+               if (sparse && pos >= data_end) {
+                       size_t data_size;
 
-               bytes_read = llapi_mirror_read(fd, src, buf, buflen, pos);
+                       data_off = llapi_mirror_data_seek(fd, src, pos,
+                                                         &data_size);
+                       if (data_off < 0) {
+                               /* Non-fatal, switch to full copy */
+                               sparse = false;
+                               continue;
+                       }
+                       if (!data_size) {
+                               /* hole at the end of file, set pos to the
+                                * data_off, so truncate block at the end
+                                * will set final dst size.
+                                */
+                               pos = data_off;
+                               break;
+                       }
+
+                       data_end = data_off + data_size;
+                       /* align by page */
+                       pos = data_off & ~(page_size - 1);
+                       data_end = ((data_end - 1) | (page_size - 1)) + 1;
+                       to_read = MIN(data_end - pos, buflen);
+               } else {
+                       to_read = buflen;
+               }
+
+               bytes_read = llapi_mirror_read(fd, src, buf, to_read, pos);
                if (!bytes_read) { /* end of file */
                        break;
                } else if (bytes_read < 0) {
@@ -252,7 +344,7 @@ ssize_t llapi_mirror_copy_many(int fd, unsigned int src, unsigned int *dst,
 
                /* round up to page align to make direct IO happy.
                 * this implies the last segment to write. */
-               to_write = (bytes_read + page_size - 1) & ~(page_size - 1);
+               to_write = ((bytes_read - 1) | (page_size - 1)) + 1;
 
                for (i = 0; i < nr; i++) {
                        ssize_t written;
@@ -268,12 +360,10 @@ ssize_t llapi_mirror_copy_many(int fd, unsigned int src, unsigned int *dst,
                                i--;
                                continue;
                        }
-
                        assert(written == to_write);
                }
-
                pos += bytes_read;
-               eof = bytes_read < buflen;
+               eof = bytes_read < to_read;
        }
 
        free(buf);