| Message ID | 9b89157957abcc87a6ea0530989a4984794484cd.1452078012.git.zhaolei@cn.fujitsu.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On Wed, Jan 6, 2016 at 11:00 AM, Zhao Lei <zhaolei@cn.fujitsu.com> wrote: > btrfs failed in xfstests btrfs/080 with -o nodatacow. > > Can be reproduced by following script: > DEV=/dev/vdg > MNT=/mnt/tmp > > umount $DEV &>/dev/null > mkfs.btrfs -f $DEV > mount -o nodatacow $DEV $MNT > > dd if=/dev/zero of=$MNT/test bs=1 count=2048 & > btrfs subvolume snapshot -r $MNT $MNT/test_snap & > wait > -- > We can see dd failed on NO_SPACE. > > Reason: > __btrfs_buffered_write should run cow write when no_cow impossible, > and current code is designed with above logic. > But check_can_nocow() have 2 type of return value(0 and <0) on > can_not_no_cow, and current code only continue write on first case, > the second case happened in doing subvolume. > > Fix: > Continue write when check_can_nocow() return 0 and <0. > > Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Could you please submit a test case for xfstests as well? Thanks. > --- > fs/btrfs/file.c | 37 +++++++++++++++++-------------------- > 1 file changed, 17 insertions(+), 20 deletions(-) > > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index 977e715..11fd981 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c > @@ -1516,27 +1516,24 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, > > reserve_bytes = num_pages << PAGE_CACHE_SHIFT; > > - if (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | > - BTRFS_INODE_PREALLOC)) { > - ret = check_can_nocow(inode, pos, &write_bytes); > - if (ret < 0) > - break; > - if (ret > 0) { > - /* > - * For nodata cow case, no need to reserve > - * data space. > - */ > - only_release_metadata = true; > - /* > - * our prealloc extent may be smaller than > - * write_bytes, so scale down. > - */ > - num_pages = DIV_ROUND_UP(write_bytes + offset, > - PAGE_CACHE_SIZE); > - reserve_bytes = num_pages << PAGE_CACHE_SHIFT; > - goto reserve_metadata; > - } > + if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | > + BTRFS_INODE_PREALLOC)) && > + check_can_nocow(inode, pos, &write_bytes) > 0) { > + /* > + * For nodata cow case, no need to reserve > + * data space. > + */ > + only_release_metadata = true; > + /* > + * our prealloc extent may be smaller than > + * write_bytes, so scale down. > + */ > + num_pages = DIV_ROUND_UP(write_bytes + offset, > + PAGE_CACHE_SIZE); > + reserve_bytes = num_pages << PAGE_CACHE_SHIFT; > + goto reserve_metadata; > } > + > ret = btrfs_check_data_free_space(inode, pos, write_bytes); > if (ret < 0) > break; > -- > 1.8.5.1 > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
Hi, Filipe Manana > -----Original Message----- > From: Filipe Manana [mailto:fdmanana@gmail.com] > Sent: Thursday, January 21, 2016 4:49 AM > To: Zhao Lei <zhaolei@cn.fujitsu.com> > Cc: linux-btrfs@vger.kernel.org > Subject: Re: [PATCH 1/3] btrfs: Continue write in case of can_not_nocow > > On Wed, Jan 6, 2016 at 11:00 AM, Zhao Lei <zhaolei@cn.fujitsu.com> wrote: > > btrfs failed in xfstests btrfs/080 with -o nodatacow. > > > > Can be reproduced by following script: > > DEV=/dev/vdg > > MNT=/mnt/tmp > > > > umount $DEV &>/dev/null > > mkfs.btrfs -f $DEV > > mount -o nodatacow $DEV $MNT > > > > dd if=/dev/zero of=$MNT/test bs=1 count=2048 & > > btrfs subvolume snapshot -r $MNT $MNT/test_snap & > > wait > > -- > > We can see dd failed on NO_SPACE. > > > > Reason: > > __btrfs_buffered_write should run cow write when no_cow impossible, > > and current code is designed with above logic. > > But check_can_nocow() have 2 type of return value(0 and <0) on > > can_not_no_cow, and current code only continue write on first case, > > the second case happened in doing subvolume. > > > > Fix: > > Continue write when check_can_nocow() return 0 and <0. > > > > Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> > Reviewed-by: Filipe Manana <fdmanana@suse.com> > Thanks for review. > Could you please submit a test case for xfstests as well? btrfs/080 with -o nodatacow already can trigger this bug. Thanks Zhaolei > Thanks. > > > --- > > fs/btrfs/file.c | 37 +++++++++++++++++-------------------- > > 1 file changed, 17 insertions(+), 20 deletions(-) > > > > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 977e715..11fd981 > > 100644 > > --- a/fs/btrfs/file.c > > +++ b/fs/btrfs/file.c > > @@ -1516,27 +1516,24 @@ static noinline ssize_t > > __btrfs_buffered_write(struct file *file, > > > > reserve_bytes = num_pages << PAGE_CACHE_SHIFT; > > > > - if (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | > > - > BTRFS_INODE_PREALLOC)) { > > - ret = check_can_nocow(inode, pos, > &write_bytes); > > - if (ret < 0) > > - break; > > - if (ret > 0) { > > - /* > > - * For nodata cow case, no need to > reserve > > - * data space. > > - */ > > - only_release_metadata = true; > > - /* > > - * our prealloc extent may be smaller > than > > - * write_bytes, so scale down. > > - */ > > - num_pages = > DIV_ROUND_UP(write_bytes + offset, > > - > PAGE_CACHE_SIZE); > > - reserve_bytes = num_pages << > PAGE_CACHE_SHIFT; > > - goto reserve_metadata; > > - } > > + if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW > | > > + > BTRFS_INODE_PREALLOC)) && > > + check_can_nocow(inode, pos, &write_bytes) > 0) { > > + /* > > + * For nodata cow case, no need to reserve > > + * data space. > > + */ > > + only_release_metadata = true; > > + /* > > + * our prealloc extent may be smaller than > > + * write_bytes, so scale down. > > + */ > > + num_pages = DIV_ROUND_UP(write_bytes + > offset, > > + > PAGE_CACHE_SIZE); > > + reserve_bytes = num_pages << > PAGE_CACHE_SHIFT; > > + goto reserve_metadata; > > } > > + > > ret = btrfs_check_data_free_space(inode, pos, > write_bytes); > > if (ret < 0) > > break; > > -- > > 1.8.5.1 > > > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-btrfs" > > in the body of a message to majordomo@vger.kernel.org More majordomo > > info at http://vger.kernel.org/majordomo-info.html > > > > -- > Filipe David Manana, > > "Reasonable men adapt themselves to the world. > Unreasonable men adapt the world to themselves. > That's why all progress depends on unreasonable men." -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, 6 Jan 2016 19:00:17 +0800 Zhao Lei <zhaolei@cn.fujitsu.com> wrote: > btrfs failed in xfstests btrfs/080 with -o nodatacow. > > Can be reproduced by following script: > DEV=/dev/vdg > MNT=/mnt/tmp > > umount $DEV &>/dev/null > mkfs.btrfs -f $DEV > mount -o nodatacow $DEV $MNT > > dd if=/dev/zero of=$MNT/test bs=1 count=2048 & > btrfs subvolume snapshot -r $MNT $MNT/test_snap & > wait > -- > We can see dd failed on NO_SPACE. > > Reason: > __btrfs_buffered_write should run cow write when no_cow impossible, > and current code is designed with above logic. > But check_can_nocow() have 2 type of return value(0 and <0) on > can_not_no_cow, and current code only continue write on first case, > the second case happened in doing subvolume. > > Fix: > Continue write when check_can_nocow() return 0 and <0. > > Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> Guys please don't forget about this patch. It solves real problem for people, http://www.spinics.net/lists/linux-btrfs/msg51276.html http://www.spinics.net/lists/linux-btrfs/msg51819.html but it's not in 4.4.1, not in 4.4.2... and now not in 4.4.3 > --- > fs/btrfs/file.c | 37 +++++++++++++++++-------------------- > 1 file changed, 17 insertions(+), 20 deletions(-) > > diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c > index 977e715..11fd981 100644 > --- a/fs/btrfs/file.c > +++ b/fs/btrfs/file.c > @@ -1516,27 +1516,24 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, > > reserve_bytes = num_pages << PAGE_CACHE_SHIFT; > > - if (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | > - BTRFS_INODE_PREALLOC)) { > - ret = check_can_nocow(inode, pos, &write_bytes); > - if (ret < 0) > - break; > - if (ret > 0) { > - /* > - * For nodata cow case, no need to reserve > - * data space. > - */ > - only_release_metadata = true; > - /* > - * our prealloc extent may be smaller than > - * write_bytes, so scale down. > - */ > - num_pages = DIV_ROUND_UP(write_bytes + offset, > - PAGE_CACHE_SIZE); > - reserve_bytes = num_pages << PAGE_CACHE_SHIFT; > - goto reserve_metadata; > - } > + if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | > + BTRFS_INODE_PREALLOC)) && > + check_can_nocow(inode, pos, &write_bytes) > 0) { > + /* > + * For nodata cow case, no need to reserve > + * data space. > + */ > + only_release_metadata = true; > + /* > + * our prealloc extent may be smaller than > + * write_bytes, so scale down. > + */ > + num_pages = DIV_ROUND_UP(write_bytes + offset, > + PAGE_CACHE_SIZE); > + reserve_bytes = num_pages << PAGE_CACHE_SHIFT; > + goto reserve_metadata; > } > + > ret = btrfs_check_data_free_space(inode, pos, write_bytes); > if (ret < 0) > break;
On Fri, Feb 26, 2016 at 10:41:31AM +0500, Roman Mamedov wrote: > On Wed, 6 Jan 2016 19:00:17 +0800 > Zhao Lei <zhaolei@cn.fujitsu.com> wrote: > > > btrfs failed in xfstests btrfs/080 with -o nodatacow. > > > > Can be reproduced by following script: > > DEV=/dev/vdg > > MNT=/mnt/tmp > > > > umount $DEV &>/dev/null > > mkfs.btrfs -f $DEV > > mount -o nodatacow $DEV $MNT > > > > dd if=/dev/zero of=$MNT/test bs=1 count=2048 & > > btrfs subvolume snapshot -r $MNT $MNT/test_snap & > > wait > > -- > > We can see dd failed on NO_SPACE. > > > > Reason: > > __btrfs_buffered_write should run cow write when no_cow impossible, > > and current code is designed with above logic. > > But check_can_nocow() have 2 type of return value(0 and <0) on > > can_not_no_cow, and current code only continue write on first case, > > the second case happened in doing subvolume. > > > > Fix: > > Continue write when check_can_nocow() return 0 and <0. > > > > Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> > > Guys please don't forget about this patch. It solves real problem for people, > http://www.spinics.net/lists/linux-btrfs/msg51276.html > http://www.spinics.net/lists/linux-btrfs/msg51819.html > but it's not in 4.4.1, not in 4.4.2... and now not in 4.4.3 Dave already has it queued for the next merge window. Thanks! -chris -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 977e715..11fd981 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -1516,27 +1516,24 @@ static noinline ssize_t __btrfs_buffered_write(struct file *file, reserve_bytes = num_pages << PAGE_CACHE_SHIFT; - if (BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | - BTRFS_INODE_PREALLOC)) { - ret = check_can_nocow(inode, pos, &write_bytes); - if (ret < 0) - break; - if (ret > 0) { - /* - * For nodata cow case, no need to reserve - * data space. - */ - only_release_metadata = true; - /* - * our prealloc extent may be smaller than - * write_bytes, so scale down. - */ - num_pages = DIV_ROUND_UP(write_bytes + offset, - PAGE_CACHE_SIZE); - reserve_bytes = num_pages << PAGE_CACHE_SHIFT; - goto reserve_metadata; - } + if ((BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | + BTRFS_INODE_PREALLOC)) && + check_can_nocow(inode, pos, &write_bytes) > 0) { + /* + * For nodata cow case, no need to reserve + * data space. + */ + only_release_metadata = true; + /* + * our prealloc extent may be smaller than + * write_bytes, so scale down. + */ + num_pages = DIV_ROUND_UP(write_bytes + offset, + PAGE_CACHE_SIZE); + reserve_bytes = num_pages << PAGE_CACHE_SHIFT; + goto reserve_metadata; } + ret = btrfs_check_data_free_space(inode, pos, write_bytes); if (ret < 0) break;
btrfs failed in xfstests btrfs/080 with -o nodatacow. Can be reproduced by following script: DEV=/dev/vdg MNT=/mnt/tmp umount $DEV &>/dev/null mkfs.btrfs -f $DEV mount -o nodatacow $DEV $MNT dd if=/dev/zero of=$MNT/test bs=1 count=2048 & btrfs subvolume snapshot -r $MNT $MNT/test_snap & wait -- We can see dd failed on NO_SPACE. Reason: __btrfs_buffered_write should run cow write when no_cow impossible, and current code is designed with above logic. But check_can_nocow() have 2 type of return value(0 and <0) on can_not_no_cow, and current code only continue write on first case, the second case happened in doing subvolume. Fix: Continue write when check_can_nocow() return 0 and <0. Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com> --- fs/btrfs/file.c | 37 +++++++++++++++++-------------------- 1 file changed, 17 insertions(+), 20 deletions(-)