From a03083a0170d86ee1baa73476a48e715af665ddb Mon Sep 17 00:00:00 2001 From: Jeff Cody Date: Tue, 3 Apr 2018 00:37:26 -0400 Subject: [PATCH] block: handle invalid lseek returns gracefully 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) { /*