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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-14 12:45:25 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-14 12:45:25 -0800 |
| commit | d05c5f7ba164aed3db02fb188c26d0dd94f5455b (patch) | |
| tree | 1f31fa0312d525122ac601a321236d9d1cb695d2 | |
| parent | 7ae123edd37a47e178eb9a6631fe4a7108262c10 (diff) | |
| download | lwn-d05c5f7ba164aed3db02fb188c26d0dd94f5455b.tar.gz lwn-d05c5f7ba164aed3db02fb188c26d0dd94f5455b.zip | |
vfs,mm: fix return value of read() at s_maxbytes
We truncated the possible read iterator to s_maxbytes in commit
c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()"),
but our end condition handling was wrong: it's not an error to try to
read at the end of the file.
Reading past the end should return EOF (0), not EINVAL.
See for example
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1649342
http://lists.gnu.org/archive/html/bug-coreutils/2016-12/msg00008.html
where a md5sum of a maximally sized file fails because the final read is
exactly at s_maxbytes.
Fixes: c2a9737f45e2 ("vfs,mm: fix a dead loop in truncate_inode_pages_range()")
Reported-by: Joseph Salisbury <joseph.salisbury@canonical.com>
Cc: Wei Fang <fangwei1@huawei.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
| -rw-r--r-- | mm/filemap.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index 69568388c699..b06517b7f97f 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1637,7 +1637,7 @@ static ssize_t do_generic_file_read(struct file *filp, loff_t *ppos, int error = 0; if (unlikely(*ppos >= inode->i_sb->s_maxbytes)) - return -EINVAL; + return 0; iov_iter_truncate(iter, inode->i_sb->s_maxbytes); index = *ppos >> PAGE_SHIFT; |