* [bug report] btrfs: enable nowait async buffered writes
@ 2022-09-23 14:53 Dan Carpenter
2022-09-26 17:21 ` Stefan Roesch
0 siblings, 1 reply; 2+ messages in thread
From: Dan Carpenter @ 2022-09-23 14:53 UTC (permalink / raw)
To: shr; +Cc: linux-btrfs
Hello Stefan Roesch,
The patch 8bf465b1c880: "btrfs: enable nowait async buffered writes"
from Sep 12, 2022, leads to the following Smatch static checker
warning:
fs/btrfs/file.c:2113 btrfs_do_write_iter()
warn: refcount leak 'inode->sync_writers.counter': lines='2113'
fs/btrfs/file.c
2092 ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
2093 const struct btrfs_ioctl_encoded_io_args *encoded)
2094 {
2095 struct file *file = iocb->ki_filp;
2096 struct btrfs_inode *inode = BTRFS_I(file_inode(file));
2097 ssize_t num_written, num_sync;
2098 const bool sync = iocb_is_dsync(iocb);
2099
2100 /*
2101 * If the fs flips readonly due to some impossible error, although we
2102 * have opened a file as writable, we have to stop this write operation
2103 * to ensure consistency.
2104 */
2105 if (BTRFS_FS_ERROR(inode->root->fs_info))
2106 return -EROFS;
2107
2108 if (sync)
2109 atomic_inc(&inode->sync_writers);
2110
2111 if (encoded) {
2112 if (iocb->ki_flags & IOCB_NOWAIT)
--> 2113 return -EOPNOTSUPP;
This check used to happen before the atomic_inc(&inode->sync_writers);
2114
2115 num_written = btrfs_encoded_write(iocb, from, encoded);
2116 num_sync = encoded->len;
2117 } else if (iocb->ki_flags & IOCB_DIRECT) {
2118 num_written = btrfs_direct_write(iocb, from);
2119 num_sync = num_written;
2120 } else {
2121 num_written = btrfs_buffered_write(iocb, from);
2122 num_sync = num_written;
2123 }
2124
2125 btrfs_set_inode_last_sub_trans(inode);
2126
2127 if (num_sync > 0) {
2128 num_sync = generic_write_sync(iocb, num_sync);
2129 if (num_sync < 0)
2130 num_written = num_sync;
2131 }
2132
2133 if (sync)
2134 atomic_dec(&inode->sync_writers);
2135
2136 current->backing_dev_info = NULL;
2137 return num_written;
2138 }
regards,
dan carpenter
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [bug report] btrfs: enable nowait async buffered writes
2022-09-23 14:53 [bug report] btrfs: enable nowait async buffered writes Dan Carpenter
@ 2022-09-26 17:21 ` Stefan Roesch
0 siblings, 0 replies; 2+ messages in thread
From: Stefan Roesch @ 2022-09-26 17:21 UTC (permalink / raw)
To: Dan Carpenter; +Cc: linux-btrfs
On 9/23/22 7:53 AM, Dan Carpenter wrote:
> >
> Hello Stefan Roesch,
>
> The patch 8bf465b1c880: "btrfs: enable nowait async buffered writes"
> from Sep 12, 2022, leads to the following Smatch static checker
> warning:
>
> fs/btrfs/file.c:2113 btrfs_do_write_iter()
> warn: refcount leak 'inode->sync_writers.counter': lines='2113'
>
> fs/btrfs/file.c
> 2092 ssize_t btrfs_do_write_iter(struct kiocb *iocb, struct iov_iter *from,
> 2093 const struct btrfs_ioctl_encoded_io_args *encoded)
> 2094 {
> 2095 struct file *file = iocb->ki_filp;
> 2096 struct btrfs_inode *inode = BTRFS_I(file_inode(file));
> 2097 ssize_t num_written, num_sync;
> 2098 const bool sync = iocb_is_dsync(iocb);
> 2099
> 2100 /*
> 2101 * If the fs flips readonly due to some impossible error, although we
> 2102 * have opened a file as writable, we have to stop this write operation
> 2103 * to ensure consistency.
> 2104 */
> 2105 if (BTRFS_FS_ERROR(inode->root->fs_info))
> 2106 return -EROFS;
> 2107
> 2108 if (sync)
> 2109 atomic_inc(&inode->sync_writers);
> 2110
> 2111 if (encoded) {
> 2112 if (iocb->ki_flags & IOCB_NOWAIT)
> --> 2113 return -EOPNOTSUPP;
>
> This check used to happen before the atomic_inc(&inode->sync_writers);
>
Thanks Dan, I sent out a fix for this issue.
--Stefan
> 2114
> 2115 num_written = btrfs_encoded_write(iocb, from, encoded);
> 2116 num_sync = encoded->len;
> 2117 } else if (iocb->ki_flags & IOCB_DIRECT) {
> 2118 num_written = btrfs_direct_write(iocb, from);
> 2119 num_sync = num_written;
> 2120 } else {
> 2121 num_written = btrfs_buffered_write(iocb, from);
> 2122 num_sync = num_written;
> 2123 }
> 2124
> 2125 btrfs_set_inode_last_sub_trans(inode);
> 2126
> 2127 if (num_sync > 0) {
> 2128 num_sync = generic_write_sync(iocb, num_sync);
> 2129 if (num_sync < 0)
> 2130 num_written = num_sync;
> 2131 }
> 2132
> 2133 if (sync)
> 2134 atomic_dec(&inode->sync_writers);
> 2135
> 2136 current->backing_dev_info = NULL;
> 2137 return num_written;
> 2138 }
>
> regards,
> dan carpenter
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2022-09-26 17:50 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-09-23 14:53 [bug report] btrfs: enable nowait async buffered writes Dan Carpenter
2022-09-26 17:21 ` Stefan Roesch
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).