[PATCH] efs: fix direct extent lookup for indirect extents

[PATCH] efs: fix direct extent lookup for indirect extents

[Keshav Verma]

The loop that finds the direct extent containing an indirect extent used
cur < ibase as its condition. Since ibase starts at zero, the loop never
advances for normal non-negative cur values, so only the first direct
extent is considered.

Iterate over the direct extents and stop when cur falls within the range
covered by the current direct extent.

Signed-off-by: Keshav Verma <iganschel@gmail.com>
---
 fs/efs/inode.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/efs/inode.c b/fs/efs/inode.c
index 4b132729e638..16b5ee10e323 100644
--- a/fs/efs/inode.c
+++ b/fs/efs/inode.c
@@ -254,9 +254,14 @@ efs_block_t efs_map_block(struct inode *inode, efs_block_t block) {
 		 *
 		 */
 		ibase = 0;
-		for(dirext = 0; cur < ibase && dirext < direxts; dirext++) {
-			ibase += in->extents[dirext].cooked.ex_length *
+		for (dirext = 0; dirext < direxts; dirext++) {
+			int entries = in->extents[dirext].cooked.ex_length *
 				(EFS_BLOCKSIZE / sizeof(efs_extent));
+
+			if (cur < ibase + entries)
+				break;
+
+			ibase += entries;
 		}
 
 		if (dirext == direxts) {
-- 
2.39.5

Re: [PATCH] efs: fix direct extent lookup for indirect extents

[Matthew Wilcox]

On Fri, Jun 19, 2026 at 01:00:05AM +0530, Keshav Verma wrote:
> The loop that finds the direct extent containing an indirect extent used
> cur < ibase as its condition. Since ibase starts at zero, the loop never
> advances for normal non-negative cur values, so only the first direct
> extent is considered.
> 
> Iterate over the direct extents and stop when cur falls within the range
> covered by the current direct extent.

Nah.

https://lore.kernel.org/linux-fsdevel/20260618211822.3599089-1-willy@infradead.org/

Re: [PATCH] efs: fix direct extent lookup for indirect extents

[Keshav Verma]

On Fri, Jun 19, 2026 at 2:49 AM Matthew Wilcox <willy@infradead.org> wrote:
>
>
> Nah.
>
> https://lore.kernel.org/linux-fsdevel/20260618211822.3599089-1-willy@infradead.org/

Thanks, I missed your EFS removal patch.

I'll drop this one.

Thanks,
Keshav