Messages in this thread | | | Date | Sat, 28 Jan 2023 10:07:48 +0800 | Subject | Re: [f2fs-dev] [PATCH] f2fs: synchronize atomic write aborts | From | Chao Yu <> |
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Hi Daeho, Jaegeuk,
Please take a look at patchset in below link:
https://lore.kernel.org/linux-f2fs-devel/20230109034453.490176-1-chao@kernel.org/T/#t
In PATCH 4/5, I'm trying to fix the same issue w/ alternative way, let me know your preference. :)
One comment as below.
On 2023/1/13 8:49, Daeho Jeong wrote: > From: Daeho Jeong <daehojeong@google.com> > > To fix a race condition between atomic write aborts, I use the inode > lock and make COW inode to be re-usable thoroughout the whole > atomic file inode lifetime. > > Reported-by: syzbot+823000d23b3400619f7c@syzkaller.appspotmail.com > Fixes: 3db1de0e582c ("f2fs: change the current atomic write way") > Signed-off-by: Daeho Jeong <daehojeong@google.com> > --- > fs/f2fs/file.c | 43 ++++++++++++++++++++++++++++--------------- > fs/f2fs/inode.c | 11 +++++++++-- > fs/f2fs/segment.c | 3 --- > fs/f2fs/super.c | 2 -- > 4 files changed, 37 insertions(+), 22 deletions(-) > > diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c > index ecbc8c135b49..ff072a9ed258 100644 > --- a/fs/f2fs/file.c > +++ b/fs/f2fs/file.c > @@ -1866,7 +1866,10 @@ static int f2fs_release_file(struct inode *inode, struct file *filp) > atomic_read(&inode->i_writecount) != 1) > return 0; > > + inode_lock(inode); > f2fs_abort_atomic_write(inode, true); > + inode_unlock(inode); > + > return 0; > } > > @@ -1880,8 +1883,11 @@ static int f2fs_file_flush(struct file *file, fl_owner_t id) > * until all the writers close its file. Since this should be done > * before dropping file lock, it needs to do in ->flush. > */ > - if (F2FS_I(inode)->atomic_write_task == current) > + if (F2FS_I(inode)->atomic_write_task == current) { > + inode_lock(inode); > f2fs_abort_atomic_write(inode, true); > + inode_unlock(inode); > + } > return 0; > } > > @@ -2087,19 +2093,28 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate) > goto out; > } > > - /* Create a COW inode for atomic write */ > - pinode = f2fs_iget(inode->i_sb, fi->i_pino); > - if (IS_ERR(pinode)) { > - f2fs_up_write(&fi->i_gc_rwsem[WRITE]); > - ret = PTR_ERR(pinode); > - goto out; > - } > + /* Check if the inode already has a COW inode */ > + if (fi->cow_inode == NULL) { > + /* Create a COW inode for atomic write */ > + pinode = f2fs_iget(inode->i_sb, fi->i_pino); > + if (IS_ERR(pinode)) { > + f2fs_up_write(&fi->i_gc_rwsem[WRITE]); > + ret = PTR_ERR(pinode); > + goto out; > + } > > - ret = f2fs_get_tmpfile(mnt_userns, pinode, &fi->cow_inode); > - iput(pinode); > - if (ret) { > - f2fs_up_write(&fi->i_gc_rwsem[WRITE]); > - goto out; > + ret = f2fs_get_tmpfile(mnt_userns, pinode, &fi->cow_inode); > + iput(pinode); > + if (ret) { > + f2fs_up_write(&fi->i_gc_rwsem[WRITE]); > + goto out; > + } > + > + set_inode_flag(fi->cow_inode, FI_COW_FILE); > + clear_inode_flag(fi->cow_inode, FI_INLINE_DATA); > + } else { > + /* Reuse the already created COW inode */ > + f2fs_do_truncate_blocks(fi->cow_inode, 0, true); > } > > f2fs_write_inode(inode, NULL); > @@ -2107,8 +2122,6 @@ static int f2fs_ioc_start_atomic_write(struct file *filp, bool truncate) > stat_inc_atomic_inode(inode); > > set_inode_flag(inode, FI_ATOMIC_FILE); > - set_inode_flag(fi->cow_inode, FI_COW_FILE); > - clear_inode_flag(fi->cow_inode, FI_INLINE_DATA); > > isize = i_size_read(inode); > fi->original_i_size = isize; > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c > index ff6cf66ed46b..4921f7209e28 100644 > --- a/fs/f2fs/inode.c > +++ b/fs/f2fs/inode.c > @@ -766,11 +766,18 @@ int f2fs_write_inode(struct inode *inode, struct writeback_control *wbc) > void f2fs_evict_inode(struct inode *inode) > { > struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > - nid_t xnid = F2FS_I(inode)->i_xattr_nid; > + struct f2fs_inode_info *fi = F2FS_I(inode); > + nid_t xnid = fi->i_xattr_nid; > int err = 0; > > f2fs_abort_atomic_write(inode, true); > > + if (fi->cow_inode) { > + clear_inode_flag(fi->cow_inode, FI_COW_FILE); > + iput(fi->cow_inode); > + fi->cow_inode = NULL; > + } > + > trace_f2fs_evict_inode(inode); > truncate_inode_pages_final(&inode->i_data); > > @@ -857,7 +864,7 @@ void f2fs_evict_inode(struct inode *inode) > stat_dec_inline_inode(inode); > stat_dec_compr_inode(inode); > stat_sub_compr_blocks(inode, > - atomic_read(&F2FS_I(inode)->i_compr_blocks)); > + atomic_read(&fi->i_compr_blocks)); > > if (likely(!f2fs_cp_error(sbi) && > !is_sbi_flag_set(sbi, SBI_CP_DISABLED))) > diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > index ae3c4e5474ef..536d7c674b04 100644 > --- a/fs/f2fs/segment.c > +++ b/fs/f2fs/segment.c > @@ -192,9 +192,6 @@ void f2fs_abort_atomic_write(struct inode *inode, bool clean) > if (!f2fs_is_atomic_file(inode)) > return; > > - clear_inode_flag(fi->cow_inode, FI_COW_FILE); > - iput(fi->cow_inode); > - fi->cow_inode = NULL; > release_atomic_write_cnt(inode); > clear_inode_flag(inode, FI_ATOMIC_COMMITTED); > clear_inode_flag(inode, FI_ATOMIC_REPLACE); > diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > index 1f812b9ce985..10463f084d30 100644 > --- a/fs/f2fs/super.c > +++ b/fs/f2fs/super.c > @@ -1430,8 +1430,6 @@ static int f2fs_drop_inode(struct inode *inode) > atomic_inc(&inode->i_count); > spin_unlock(&inode->i_lock); > > - f2fs_abort_atomic_write(inode, true);
In order to avoid caching obsolete page of cow_inode, how about truncating them here?
if (f2fs_is_atomic_file() && cow_inode) truncate_inode_pages_final(&cow_inode->i_data);
Thanks,
> - > /* should remain fi->extent_tree for writepage */ > f2fs_destroy_extent_node(inode); >
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