Re: [PATCH 1/7] BTRFS: Fix lseek return value for error

[Chris Mason <chris.mason@oracle.com>]

Excerpts from Andi Kleen's message of 2011-09-19 13:52:03 -0400:
> > Thanks everyone, I've put Jeff's last version of this in my queue.
> 
> Can you post the version you merged? The previous ones all had issues.

https://github.com/chrismason/linux/commit/48802c8ae2a9d618ec734a61283d645ad527e06c

This was the last one sent, I thought it combined all the fixes.


commit 48802c8ae2a9d618ec734a61283d645ad527e06c
Author: Jeff Liu <jeff.liu@oracle.com>
Date:   Sun Sep 18 10:34:02 2011 -0400

    BTRFS: Fix lseek return value for error
    
    The recent reworking of btrfs' lseek lead to incorrect
    values being returned.  This adds checks for seeking
    beyond EOF in SEEK_HOLE and makes sure the error
    values come back correct.
    
    Andi Kleen also sent in similar patches.
    
    Signed-off-by: Jie Liu <jeff.liu@oracle.com>
    Reported-by: Andi Kleen <ak@linux.intel.com>
    Signed-off-by: Chris Mason <chris.mason@oracle.com>

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 3c3abff..a381cd2 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1817,6 +1817,11 @@ static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
 		goto out;
 	case SEEK_DATA:
 	case SEEK_HOLE:
+		if (offset >= i_size_read(inode)) {
+			mutex_unlock(&inode->i_mutex);
+			return -ENXIO;
+		}
+
 		ret = find_desired_extent(inode, &offset, origin);
 		if (ret) {
 			mutex_unlock(&inode->i_mutex);
@@ -1825,11 +1830,11 @@ static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int origin)
 	}
 
 	if (offset < 0 && !(file->f_mode & FMODE_UNSIGNED_OFFSET)) {
-		ret = -EINVAL;
+		offset = -EINVAL;
 		goto out;
 	}
 	if (offset > inode->i_sb->s_maxbytes) {
-		ret = -EINVAL;
+		offset = -EINVAL;
 		goto out;
 	}