nilfs2: fiemap support
This adds fiemap to nilfs. Two new functions, nilfs_fiemap and
nilfs_find_uncommitted_extent are added.
nilfs_fiemap() implements the fiemap inode operation, and
nilfs_find_uncommitted_extent() helps to get a range of data blocks
whose physical location has not been determined.
nilfs_fiemap() collects extent information by looping through
nilfs_bmap_lookup_contig and nilfs_find_uncommitted_extent routines.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 1a546a8..b2a8150 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -916,3 +916,134 @@
nilfs_mark_inode_dirty(inode);
nilfs_transaction_commit(inode->i_sb); /* never fails */
}
+
+int nilfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
+ __u64 start, __u64 len)
+{
+ struct the_nilfs *nilfs = NILFS_I_NILFS(inode);
+ __u64 logical = 0, phys = 0, size = 0;
+ __u32 flags = 0;
+ loff_t isize;
+ sector_t blkoff, end_blkoff;
+ sector_t delalloc_blkoff;
+ unsigned long delalloc_blklen;
+ unsigned int blkbits = inode->i_blkbits;
+ int ret, n;
+
+ ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
+ if (ret)
+ return ret;
+
+ mutex_lock(&inode->i_mutex);
+
+ isize = i_size_read(inode);
+
+ blkoff = start >> blkbits;
+ end_blkoff = (start + len - 1) >> blkbits;
+
+ delalloc_blklen = nilfs_find_uncommitted_extent(inode, blkoff,
+ &delalloc_blkoff);
+
+ do {
+ __u64 blkphy;
+ unsigned int maxblocks;
+
+ if (delalloc_blklen && blkoff == delalloc_blkoff) {
+ if (size) {
+ /* End of the current extent */
+ ret = fiemap_fill_next_extent(
+ fieinfo, logical, phys, size, flags);
+ if (ret)
+ break;
+ }
+ if (blkoff > end_blkoff)
+ break;
+
+ flags = FIEMAP_EXTENT_MERGED | FIEMAP_EXTENT_DELALLOC;
+ logical = blkoff << blkbits;
+ phys = 0;
+ size = delalloc_blklen << blkbits;
+
+ blkoff = delalloc_blkoff + delalloc_blklen;
+ delalloc_blklen = nilfs_find_uncommitted_extent(
+ inode, blkoff, &delalloc_blkoff);
+ continue;
+ }
+
+ /*
+ * Limit the number of blocks that we look up so as
+ * not to get into the next delayed allocation extent.
+ */
+ maxblocks = INT_MAX;
+ if (delalloc_blklen)
+ maxblocks = min_t(sector_t, delalloc_blkoff - blkoff,
+ maxblocks);
+ blkphy = 0;
+
+ down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+ n = nilfs_bmap_lookup_contig(
+ NILFS_I(inode)->i_bmap, blkoff, &blkphy, maxblocks);
+ up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
+
+ if (n < 0) {
+ int past_eof;
+
+ if (unlikely(n != -ENOENT))
+ break; /* error */
+
+ /* HOLE */
+ blkoff++;
+ past_eof = ((blkoff << blkbits) >= isize);
+
+ if (size) {
+ /* End of the current extent */
+
+ if (past_eof)
+ flags |= FIEMAP_EXTENT_LAST;
+
+ ret = fiemap_fill_next_extent(
+ fieinfo, logical, phys, size, flags);
+ if (ret)
+ break;
+ size = 0;
+ }
+ if (blkoff > end_blkoff || past_eof)
+ break;
+ } else {
+ if (size) {
+ if (phys && blkphy << blkbits == phys + size) {
+ /* The current extent goes on */
+ size += n << blkbits;
+ } else {
+ /* Terminate the current extent */
+ ret = fiemap_fill_next_extent(
+ fieinfo, logical, phys, size,
+ flags);
+ if (ret || blkoff > end_blkoff)
+ break;
+
+ /* Start another extent */
+ flags = FIEMAP_EXTENT_MERGED;
+ logical = blkoff << blkbits;
+ phys = blkphy << blkbits;
+ size = n << blkbits;
+ }
+ } else {
+ /* Start a new extent */
+ flags = FIEMAP_EXTENT_MERGED;
+ logical = blkoff << blkbits;
+ phys = blkphy << blkbits;
+ size = n << blkbits;
+ }
+ blkoff += n;
+ }
+ cond_resched();
+ } while (true);
+
+ /* If ret is 1 then we just hit the end of the extent array */
+ if (ret == 1)
+ ret = 0;
+
+ mutex_unlock(&inode->i_mutex);
+ return ret;
+}