Messages in this thread | | | Date | Fri, 29 Nov 2019 04:35:15 +0100 | From | Javier Gonzalez <> | Subject | Re: [PATCH] f2fs: Fix direct IO handling |
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On 26.11.2019 15:44, Jaegeuk Kim wrote: >On 11/26, Damien Le Moal wrote: >> f2fs_preallocate_blocks() identifies direct IOs using the IOCB_DIRECT >> flag for a kiocb structure. However, the file system direct IO handler >> function f2fs_direct_IO() may have decided that a direct IO has to be >> exececuted as a buffered IO using the function f2fs_force_buffered_io(). >> This is the case for instance for volumes including zoned block device >> and for unaligned write IOs with LFS mode enabled. >> >> These 2 different methods of identifying direct IOs can result in >> inconsistencies generating stale data access for direct reads after a >> direct IO write that is treated as a buffered write. Fix this >> inconsistency by combining the IOCB_DIRECT flag test with the result >> of f2fs_force_buffered_io(). >> >> Reported-by: Javier Gonzalez <javier@javigon.com> >> Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com> >> --- >> fs/f2fs/data.c | 4 +++- >> 1 file changed, 3 insertions(+), 1 deletion(-) >> >> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >> index 5755e897a5f0..8ac2d3b70022 100644 >> --- a/fs/f2fs/data.c >> +++ b/fs/f2fs/data.c >> @@ -1073,6 +1073,8 @@ int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from) >> int flag; >> int err = 0; >> bool direct_io = iocb->ki_flags & IOCB_DIRECT; >> + bool do_direct_io = direct_io && >> + !f2fs_force_buffered_io(inode, iocb, from); >> >> /* convert inline data for Direct I/O*/ >> if (direct_io) { >> @@ -1081,7 +1083,7 @@ int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from) >> return err; >> } >> >> - if (direct_io && allow_outplace_dio(inode, iocb, from)) >> + if (do_direct_io && allow_outplace_dio(inode, iocb, from)) > >It seems f2fs_force_buffered_io() includes allow_outplace_dio(). > >How about this? >--- > fs/f2fs/data.c | 13 ------------- > fs/f2fs/file.c | 35 +++++++++++++++++++++++++---------- > 2 files changed, 25 insertions(+), 23 deletions(-) > >diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c >index a034cd0ce021..fc40a72f7827 100644 >--- a/fs/f2fs/data.c >+++ b/fs/f2fs/data.c >@@ -1180,19 +1180,6 @@ int f2fs_preallocate_blocks(struct kiocb *iocb, struct iov_iter *from) > int err = 0; > bool direct_io = iocb->ki_flags & IOCB_DIRECT; > >- /* convert inline data for Direct I/O*/ >- if (direct_io) { >- err = f2fs_convert_inline_inode(inode); >- if (err) >- return err; >- } >- >- if (direct_io && allow_outplace_dio(inode, iocb, from)) >- return 0; >- >- if (is_inode_flag_set(inode, FI_NO_PREALLOC)) >- return 0; >- > map.m_lblk = F2FS_BLK_ALIGN(iocb->ki_pos); > map.m_len = F2FS_BYTES_TO_BLK(iocb->ki_pos + iov_iter_count(from)); > if (map.m_len > map.m_lblk) >diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c >index c0560d62dbee..6b32ac6c3382 100644 >--- a/fs/f2fs/file.c >+++ b/fs/f2fs/file.c >@@ -3386,18 +3386,33 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) > ret = -EAGAIN; > goto out; > } >- } else { >- preallocated = true; >- target_size = iocb->ki_pos + iov_iter_count(from); >+ goto write; >+ } > >- err = f2fs_preallocate_blocks(iocb, from); >- if (err) { >- clear_inode_flag(inode, FI_NO_PREALLOC); >- inode_unlock(inode); >- ret = err; >- goto out; >- } >+ if (is_inode_flag_set(inode, FI_NO_PREALLOC)) >+ goto write; >+ >+ if (iocb->ki_flags & IOCB_DIRECT) { >+ /* convert inline data for Direct I/O*/ >+ err = f2fs_convert_inline_inode(inode); >+ if (err) >+ goto out_err; >+ >+ if (!f2fs_force_buffered_io(inode, iocb, from)) >+ goto write; >+ } >+ preallocated = true; >+ target_size = iocb->ki_pos + iov_iter_count(from); >+ >+ err = f2fs_preallocate_blocks(iocb, from); >+ if (err) { >+out_err: >+ clear_inode_flag(inode, FI_NO_PREALLOC); >+ inode_unlock(inode); >+ ret = err; >+ goto out; > } >+write: > ret = __generic_file_write_iter(iocb, from); > clear_inode_flag(inode, FI_NO_PREALLOC); > >-- >2.19.0.605.g01d371f741-goog > This also addresses the original problem.
Tested-by: Javier González <javier@javigon.com>
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