From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:55255) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f3Osy-0006mM-UX for qemu-devel@nongnu.org; Tue, 03 Apr 2018 12:34:18 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f3Osx-0006Xu-Mw for qemu-devel@nongnu.org; Tue, 03 Apr 2018 12:34:16 -0400 From: Kevin Wolf Date: Tue, 3 Apr 2018 18:33:53 +0200 Message-Id: <20180403163400.6307-3-kwolf@redhat.com> In-Reply-To: <20180403163400.6307-1-kwolf@redhat.com> References: <20180403163400.6307-1-kwolf@redhat.com> Subject: [Qemu-devel] [PULL 2/9] block: handle invalid lseek returns gracefully List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-block@nongnu.org Cc: kwolf@redhat.com, peter.maydell@linaro.org, qemu-devel@nongnu.org From: Jeff Cody In commit 223a23c198787328ae75bc65d84edf5fde33c0b6, we implemented a workaround in the gluster driver to handle invalid values returned for SEEK_DATA or SEEK_HOLE. In some instances, these same invalid values can be seen in the posix file handler as well - for example, it has been reported on FUSE gluster mounts. Calling assert() for these invalid values is overly harsh; we can safely return -EIO and allow this case to be treated as a "learned nothing" case (e.g., D4 / H4, as commented in the code). This patch does the same thing that 223a23c198787 did for gluster.c, except in file-posix.c Signed-off-by: Jeff Cody Reviewed-by: Eric Blake Signed-off-by: Kevin Wolf --- block/file-posix.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/block/file-posix.c b/block/file-posix.c index d7fb772c14..a2f6d8a8c8 100644 --- a/block/file-posix.c +++ b/block/file-posix.c @@ -2114,7 +2114,12 @@ static int find_allocation(BlockDriverState *bs, off_t start, if (offs < 0) { return -errno; /* D3 or D4 */ } - assert(offs >= start); + + if (offs < start) { + /* This is not a valid return by lseek(). We are safe to just return + * -EIO in this case, and we'll treat it like D4. */ + return -EIO; + } if (offs > start) { /* D2: in hole, next data at offs */ @@ -2146,7 +2151,12 @@ static int find_allocation(BlockDriverState *bs, off_t start, if (offs < 0) { return -errno; /* D1 and (H3 or H4) */ } - assert(offs >= start); + + if (offs < start) { + /* This is not a valid return by lseek(). We are safe to just return + * -EIO in this case, and we'll treat it like H4. */ + return -EIO; + } if (offs > start) { /* -- 2.13.6