From: NeilBrown <neilb@suse.de>
Date: Wed, 23 Jun 2010 06:20:28 +0000 (+1000)
Subject: Revise error returns for allocation failure.
X-Git-Url: http://git.neil.brown.name/?a=commitdiff_plain;h=d611d8d603759ead8e07d7a678304ceed5329da2;p=LaFS.git

Revise error returns for allocation failure.

lafs_prealloc, like lafs_space_alloc, just succeeds or fails, it
doesn't choose the error type.

lafs_cluster_update_pin and lafs_reserve_block need to indicate
either -ENOSPC or -EAGAIN depending on context.

Signed-off-by: NeilBrown <neilb@suse.de>
---

diff --git a/block.c b/block.c
index 2712451..89431fe 100644
--- a/block.c
+++ b/block.c
@@ -366,29 +366,26 @@ lafs_reserve_block(struct block *b, int alloc_type)
 	else
 		err = lafs_setparent(dblk(b));
 
-	if (test_bit(B_Realloc, &b->flags))
-		alloc_type = CleanSpace;
-	if (alloc_type == NewSpace && b->physaddr)
+	/* If there is already a physaddr, or the data is
+	 * stored in the inode, then we aren't really allocating
+	 * new space.
+	 * When unlinking from a small directory, this can
+	 * be an issue.
+	 */
+	if (alloc_type == NewSpace &&
+	    (b->physaddr || (b->fileaddr == 0
+			     && LAFSI(b->inode)->depth == 0)))
 		alloc_type = ReleaseSpace;
 
-	if (alloc_type == NewSpace && !b->physaddr &&
-	    b->fileaddr == 0 &&
-	    LAFSI(b->inode)->depth == 0) {
-		/* HACK. If the file isn't growing, we can use
-		 * ReleaseSpace.  But we don't really know.
-		 * This is needed for unlink
-		 */
-		alloc_type = ReleaseSpace;
-	}
-	if (alloc_type == NewSpace && test_bit(B_InoIdx, &b->flags)) {
-		/* HACK, phys isn't necessarily set for the InoIdx block.
-		 * Is this a good way to handle that?
+	if (alloc_type == NewSpace && test_bit(B_InoIdx, &b->flags))
+		/* physaddr isn't necessarily set for the InoIdx block.
 		 */
 		alloc_type = ReleaseSpace;
-	}
 
+	/* Allocate space in the filesystem */
 	err = err ?: lafs_prealloc(b, alloc_type);
 
+	/* Allocate space in the file (and quota set) */
 	if (err == 0 && b->physaddr == 0 &&
 	    !test_bit(B_Index, &b->flags) &&
 	    !test_and_set_bit(B_Prealloc, &b->flags)) {
@@ -396,8 +393,6 @@ lafs_reserve_block(struct block *b, int alloc_type)
 		if (err)
 			clear_bit(B_Prealloc, &b->flags);
 	}
-	if (err)
-		return err;
 
 	/* Having reserved the block, we need to get a segref,
 	 * which will involve reserving those blocks too.
@@ -409,7 +404,13 @@ lafs_reserve_block(struct block *b, int alloc_type)
 	       && !test_bit(B_SegRef, &b->flags))
 		err = lafs_seg_ref_block(b, 0);
 
-	return err;
+	if (err == 0)
+		return 0;
+	if (alloc_type == CleanSpace || alloc_type == NewSpace)
+		return -ENOSPC;
+	if (alloc_type == ReleaseSpace)
+		return -EAGAIN;
+	LAFS_BUG(1, b);
 }
 
 int
diff --git a/cluster.c b/cluster.c
index 377d536..ba2f7b7 100644
--- a/cluster.c
+++ b/cluster.c
@@ -894,6 +894,7 @@ lafs_cluster_update_prepare(struct update_handle *uh, struct fs *fs,
 	uh->reserved = 0;
 	return 0;
 }
+
 int
 lafs_cluster_update_pin(struct update_handle *uh)
 {
@@ -903,7 +904,7 @@ lafs_cluster_update_pin(struct update_handle *uh)
 		uh->fs->cluster_updates++;
 		return 0;
 	}
-	return -ENOSPC;
+	return -EAGAIN;
 }
 
 static unsigned long long
diff --git a/modify.c b/modify.c
index 481057d..33b2cf8 100644
--- a/modify.c
+++ b/modify.c
@@ -1932,11 +1932,7 @@ int __must_check lafs_prealloc(struct block *blk, int why)
 	}
 	lafs_space_return(fs, credits);
 
-	/* allocation failed. */
-	if (why == NewSpace)
-		return -ENOSPC;
-	else
-		return -EAGAIN;
+	return -ENOSPC;
 }
 
 /* If a datablock is dirty and pinned to the previous phase,