Messages in this thread Patch in this message | | | Subject | Re: ext4 iomap SEEK broken [was: [GIT PULL] ext4 updates for 4.15] | From | Jiri Slaby <> | Date | Mon, 12 Feb 2018 14:34:29 +0100 |
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On 02/12/2018, 01:14 PM, Jiri Slaby wrote: > On 02/12/2018, 11:02 AM, Jiri Slaby wrote: >> Given this happens only on 32bit kernel, I assume some 32bit overflow. >> But I am unable to see it (yet). > > Just to add, a diff of strace in good and bad kernels: > @@ -655,14 +655,4 @@ > _llseek(3, 4275568640, [4286054400], SEEK_DATA) = 0 > _llseek(3, 4286054400, [4288675840], SEEK_HOLE) = 0 > _llseek(3, 4288675840, [4299161600], SEEK_DATA) = 0 > -_llseek(3, 4299161600, [4301783040], SEEK_HOLE) = 0 > +_llseek(3, 4299161600, [4299161600], SEEK_HOLE) = 2621440 > > llseek returns a very invalid value when it comes to 0x100400000.
It gets cropped to 0x400000, so:
--- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3523,7 +3523,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, iomap->flags |= IOMAP_F_DIRTY; iomap->bdev = inode->i_sb->s_bdev; iomap->dax_dev = sbi->s_daxdev; - iomap->offset = first_block << blkbits; + iomap->offset = (u64)first_block << blkbits; iomap->length = (u64)map.m_len << blkbits;
if (ret == 0) { sounds about right?
> regards, -- js suse labs
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