btrfs: Remove extent_io_ops::readpage_io_failed_hook

For data inodes this hook does nothing but to return -EAGAIN which is
used to signal to the endio routines that this bio belongs to a data
inode. If this is the case the actual retrying is handled by
bio_readpage_error. Alternatively, if this bio belongs to the btree
inode then btree_io_failed_hook just does some cleanup and doesn't retry
anything.

This patch simplifies the code flow by eliminating
readpage_io_failed_hook and instead open-coding btree_io_failed_hook in
end_bio_extent_readpage. Also eliminate some needless checks since IO is
always performed on either data inode or btree inode, both of which are
guaranteed to have their extent_io_tree::ops set.

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>

diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c
index 19b270368308d8063b536cb7aa785802f7c4364b..4bc270ef29b4ed8da59cbf4f4af30a618ef0c7f2 100644 (file)
--- a/fs/btrfs/disk-io.c
+++ b/fs/btrfs/disk-io.c
@@ -673,19 +673,6 @@ out:
        return ret;
 }
 
-static int btree_io_failed_hook(struct page *page, int failed_mirror)
-{
-       struct extent_buffer *eb;
-
-       eb = (struct extent_buffer *)page->private;
-       set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
-       eb->read_mirror = failed_mirror;
-       atomic_dec(&eb->io_pages);
-       if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD, &eb->bflags))
-               btree_readahead_hook(eb, -EIO);
-       return -EIO;    /* we fixed nothing */
-}
-
 static void end_workqueue_bio(struct bio *bio)
 {
        struct btrfs_end_io_wq *end_io_wq = bio->bi_private;
@@ -4560,7 +4547,4 @@ static const struct extent_io_ops btree_extent_io_ops = {
        /* mandatory callbacks */
        .submit_bio_hook = btree_submit_bio_hook,
        .readpage_end_io_hook = btree_readpage_end_io_hook,
-       .readpage_io_failed_hook = btree_io_failed_hook,
-
-       /* optional callbacks */
 };

diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index aef3c9866ff042b29693371f3820413189e6c5c3..582b4b1c41e08a33554dd618ec94a823d70698d3 100644 (file)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -2333,13 +2333,11 @@ struct bio *btrfs_create_repair_bio(struct inode *inode, struct bio *failed_bio,
 }
 
 /*
- * this is a generic handler for readpage errors (default
- * readpage_io_failed_hook). if other copies exist, read those and write back
- * good data to the failed position. does not investigate in remapping the
- * failed extent elsewhere, hoping the device will be smart enough to do this as
- * needed
+ * This is a generic handler for readpage errors. If other copies exist, read
+ * those and write back good data to the failed position. Does not investigate
+ * in remapping the failed extent elsewhere, hoping the device will be smart
+ * enough to do this as needed
  */
-
 static int bio_readpage_error(struct bio *failed_bio, u64 phy_offset,
                              struct page *page, u64 start, u64 end,
                              int failed_mirror)
@@ -2501,6 +2499,8 @@ static void end_bio_extent_readpage(struct bio *bio)
                struct page *page = bvec->bv_page;
                struct inode *inode = page->mapping->host;
                struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
+               bool data_inode = btrfs_ino(BTRFS_I(inode))
+                       != BTRFS_BTREE_INODE_OBJECTID;
 
                btrfs_debug(fs_info,
                        "end_bio_extent_readpage: bi_sector=%llu, err=%d, mirror=%u",
@@ -2530,7 +2530,7 @@ static void end_bio_extent_readpage(struct bio *bio)
                len = bvec->bv_len;
 
                mirror = io_bio->mirror_num;
-               if (likely(uptodate && tree->ops)) {
+               if (likely(uptodate)) {
                        ret = tree->ops->readpage_end_io_hook(io_bio, offset,
                                                              page, start, end,
                                                              mirror);
@@ -2546,38 +2546,37 @@ static void end_bio_extent_readpage(struct bio *bio)
                if (likely(uptodate))
                        goto readpage_ok;
 
-               if (tree->ops) {
-                       ret = tree->ops->readpage_io_failed_hook(page, mirror);
-                       if (ret == -EAGAIN) {
-                               /*
-                                * Data inode's readpage_io_failed_hook() always
-                                * returns -EAGAIN.
-                                *
-                                * The generic bio_readpage_error handles errors
-                                * the following way: If possible, new read
-                                * requests are created and submitted and will
-                                * end up in end_bio_extent_readpage as well (if
-                                * we're lucky, not in the !uptodate case). In
-                                * that case it returns 0 and we just go on with
-                                * the next page in our bio. If it can't handle
-                                * the error it will return -EIO and we remain
-                                * responsible for that page.
-                                */
-                               ret = bio_readpage_error(bio, offset, page,
-                                                        start, end, mirror);
-                               if (ret == 0) {
-                                       uptodate = !bio->bi_status;
-                                       offset += len;
-                                       continue;
-                               }
-                       }
+               if (data_inode) {
 
                        /*
-                        * metadata's readpage_io_failed_hook() always returns
-                        * -EIO and fixes nothing.  -EIO is also returned if
-                        * data inode error could not be fixed.
+                        * The generic bio_readpage_error handles errors the
+                        * following way: If possible, new read requests are
+                        * created and submitted and will end up in
+                        * end_bio_extent_readpage as well (if we're lucky,
+                        * not in the !uptodate case). In that case it returns
+                        * 0 and we just go on with the next page in our bio.
+                        * If it can't handle the error it will return -EIO and
+                        * we remain responsible for that page.
                         */
-                       ASSERT(ret == -EIO);
+                       ret = bio_readpage_error(bio, offset, page, start, end,
+                                                mirror);
+                       if (ret == 0) {
+                               uptodate = !bio->bi_status;
+                               offset += len;
+                               continue;
+                       }
+               } else {
+                       struct extent_buffer *eb;
+
+                       eb = (struct extent_buffer *)page->private;
+                       set_bit(EXTENT_BUFFER_READ_ERR, &eb->bflags);
+                       eb->read_mirror = mirror;
+                       atomic_dec(&eb->io_pages);
+                       if (test_and_clear_bit(EXTENT_BUFFER_READAHEAD,
+                                              &eb->bflags))
+                               btree_readahead_hook(eb, -EIO);
+
+                       ret = -EIO;
                }
 readpage_ok:
                if (likely(uptodate)) {

diff --git a/fs/btrfs/extent_io.h b/fs/btrfs/extent_io.h
index 17878eef9bcc54a01ba8abc8a50a55f6af37e542..a1d3ea5a0d329154655ca64e7d08e1c2b058f272 100644 (file)
--- a/fs/btrfs/extent_io.h
+++ b/fs/btrfs/extent_io.h
@@ -101,7 +101,6 @@ struct extent_io_ops {
        int (*readpage_end_io_hook)(struct btrfs_io_bio *io_bio, u64 phy_offset,
                                    struct page *page, u64 start, u64 end,
                                    int mirror);
-       int (*readpage_io_failed_hook)(struct page *page, int failed_mirror);
 };
 
 struct extent_io_tree {

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 6bfd37e58924821a49211c1fffd2e44e8fdc0e71..c2c96acaf2fcb40e8496913fb023e0aca723c1bb 100644 (file)
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -10409,12 +10409,6 @@ out:
        return ret;
 }
 
-__attribute__((const))
-static int btrfs_readpage_io_failed_hook(struct page *page, int failed_mirror)
-{
-       return -EAGAIN;
-}
-
 void btrfs_set_range_writeback(struct extent_io_tree *tree, u64 start, u64 end)
 {
        struct inode *inode = tree->private_data;
@@ -10810,7 +10804,6 @@ static const struct extent_io_ops btrfs_extent_io_ops = {
        /* mandatory callbacks */
        .submit_bio_hook = btrfs_submit_bio_hook,
        .readpage_end_io_hook = btrfs_readpage_end_io_hook,
-       .readpage_io_failed_hook = btrfs_readpage_io_failed_hook,
 };
 
 /*