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authorAndreas Gruenbacher <agruenba@redhat.com>2017-06-29 21:43:21 +0300
committerDarrick J. Wong <darrick.wong@oracle.com>2017-07-03 08:46:13 +0300
commit0ed3b0d45fd39142e418220f518c8959c1a5f596 (patch)
tree5c629e3654c2959be05fee0875952b419a5718a9 /fs/iomap.c
parent334fd34d76f237c0ee58dfc400d2c4e34d660544 (diff)
downloadlinux-0ed3b0d45fd39142e418220f518c8959c1a5f596.tar.xz
vfs: Add iomap_seek_hole and iomap_seek_data helpers
Filesystems can use this for implementing lseek SEEK_HOLE / SEEK_DATA support via iomap. Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com> [hch: split functions, coding style cleanups] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/iomap.c')
-rw-r--r--fs/iomap.c94
1 files changed, 94 insertions, 0 deletions
diff --git a/fs/iomap.c b/fs/iomap.c
index 4b10892967a5..432eed8f091f 100644
--- a/fs/iomap.c
+++ b/fs/iomap.c
@@ -584,6 +584,100 @@ int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi,
}
EXPORT_SYMBOL_GPL(iomap_fiemap);
+static loff_t
+iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length,
+ void *data, struct iomap *iomap)
+{
+ switch (iomap->type) {
+ case IOMAP_UNWRITTEN:
+ offset = page_cache_seek_hole_data(inode, offset, length,
+ SEEK_HOLE);
+ if (offset < 0)
+ return length;
+ /* fall through */
+ case IOMAP_HOLE:
+ *(loff_t *)data = offset;
+ return 0;
+ default:
+ return length;
+ }
+}
+
+loff_t
+iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
+{
+ loff_t size = i_size_read(inode);
+ loff_t length = size - offset;
+ loff_t ret;
+
+ /* Nothing to be found beyond the end of the file. */
+ if (offset >= size)
+ return -ENXIO;
+
+ while (length > 0) {
+ ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
+ &offset, iomap_seek_hole_actor);
+ if (ret < 0)
+ return ret;
+ if (ret == 0)
+ break;
+
+ offset += ret;
+ length -= ret;
+ }
+
+ return offset;
+}
+EXPORT_SYMBOL_GPL(iomap_seek_hole);
+
+static loff_t
+iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length,
+ void *data, struct iomap *iomap)
+{
+ switch (iomap->type) {
+ case IOMAP_HOLE:
+ return length;
+ case IOMAP_UNWRITTEN:
+ offset = page_cache_seek_hole_data(inode, offset, length,
+ SEEK_DATA);
+ if (offset < 0)
+ return length;
+ /*FALLTHRU*/
+ default:
+ *(loff_t *)data = offset;
+ return 0;
+ }
+}
+
+loff_t
+iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops)
+{
+ loff_t size = i_size_read(inode);
+ loff_t length = size - offset;
+ loff_t ret;
+
+ /* Nothing to be found beyond the end of the file. */
+ if (offset >= size)
+ return -ENXIO;
+
+ while (length > 0) {
+ ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops,
+ &offset, iomap_seek_data_actor);
+ if (ret < 0)
+ return ret;
+ if (ret == 0)
+ break;
+
+ offset += ret;
+ length -= ret;
+ }
+
+ if (length <= 0)
+ return -ENXIO;
+ return offset;
+}
+EXPORT_SYMBOL_GPL(iomap_seek_data);
+
/*
* Private flags for iomap_dio, must not overlap with the public ones in
* iomap.h: