From: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
Push inode locking and unlocking closer to where we perform the I/O. For
this we need to move the write checks inside the respective functions as
well.
pos is evaluated after generic_write_checks because O_APPEND can change
iocb->ki_pos.
Reviewed-by: Josef Bacik <josef@xxxxxxxxxxxxxx>
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@xxxxxxxx>
---
fs/btrfs/file.c | 70 +++++++++++++++++++++++++++++++------------------
1 file changed, 45 insertions(+), 25 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index a9d0950fd922..72fa1c692a53 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -1699,7 +1699,7 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
struct iov_iter *i)
{
struct file *file = iocb->ki_filp;
- loff_t pos = iocb->ki_pos;
+ loff_t pos;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
struct page **pages = NULL;
@@ -1713,14 +1713,29 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
bool only_release_metadata = false;
bool force_page_uptodate = false;
loff_t old_isize = i_size_read(inode);
+ int ilock_flags = 0;
+
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ ilock_flags |= BTRFS_ILOCK_TRY;
+
+ ret = btrfs_inode_lock(inode, ilock_flags);
+ if (ret < 0)
+ return ret;
+
+ ret = btrfs_write_check(iocb, i);
+ if (ret <= 0)
+ goto out;
+ pos = iocb->ki_pos;
nrptrs = min(DIV_ROUND_UP(iov_iter_count(i), PAGE_SIZE),
PAGE_SIZE / (sizeof(struct page *)));
nrptrs = min(nrptrs, current->nr_dirtied_pause - current->nr_dirtied);
nrptrs = max(nrptrs, 8);
pages = kmalloc_array(nrptrs, sizeof(struct page *), GFP_KERNEL);
- if (!pages)
- return -ENOMEM;
+ if (!pages) {
+ ret = -ENOMEM;
+ goto out;
+ }
while (iov_iter_count(i) > 0) {
struct extent_state *cached_state = NULL;
@@ -1937,6 +1952,8 @@ static noinline ssize_t btrfs_buffered_write(struct kiocb *iocb,
pagecache_isize_extended(inode, old_isize, iocb->ki_pos);
iocb->ki_pos += num_written;
}
+out:
+ btrfs_inode_unlock(inode, ilock_flags);
return num_written ? num_written : ret;
}
@@ -1959,15 +1976,33 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
struct file *file = iocb->ki_filp;
struct inode *inode = file_inode(file);
struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
- loff_t pos = iocb->ki_pos;
+ loff_t pos;
ssize_t written = 0;
bool relock = false;
ssize_t written_buffered;
loff_t endbyte;
int err;
+ int ilock_flags = 0;
+
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ ilock_flags |= BTRFS_ILOCK_TRY;
+
+ err = btrfs_inode_lock(inode, ilock_flags);
+ if (err < 0)
+ return err;
+
+ err = btrfs_write_check(iocb, from);
+ if (err <= 0) {
+ btrfs_inode_unlock(inode, ilock_flags);
+ goto out;
+ }
+
+ pos = iocb->ki_pos;
- if (check_direct_IO(fs_info, from, pos))
+ if (check_direct_IO(fs_info, from, pos)) {
+ btrfs_inode_unlock(inode, ilock_flags);
goto buffered;
+ }
/*
* If the write DIO is beyond the EOF, we need update
@@ -1998,8 +2033,10 @@ static ssize_t btrfs_direct_write(struct kiocb *iocb, struct iov_iter *from)
if (relock)
btrfs_inode_lock(inode, 0);
- if (written < 0 || !iov_iter_count(from))
- return written;
+ if (written < 0 || !iov_iter_count(from)) {
+ err = written;
+ goto out;
+ }
buffered:
pos = iocb->ki_pos;
@@ -2036,8 +2073,6 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
struct btrfs_root *root = BTRFS_I(inode)->root;
ssize_t num_written = 0;
const bool sync = iocb->ki_flags & IOCB_DSYNC;
- ssize_t err;
- int ilock_flags = 0;
/*
* If BTRFS flips readonly due to some impossible error,
@@ -2051,19 +2086,6 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
(iocb->ki_flags & IOCB_NOWAIT))
return -EOPNOTSUPP;
- if (iocb->ki_flags & IOCB_NOWAIT)
- ilock_flags |= BTRFS_ILOCK_TRY;
-
- err = btrfs_inode_lock(inode, ilock_flags);
- if (err < 0)
- return err;
-
- err = btrfs_write_check(iocb, from);
- if (err <= 0) {
- btrfs_inode_unlock(inode, ilock_flags);
- return err;
- }
-
if (sync)
atomic_inc(&BTRFS_I(inode)->sync_writers);
@@ -2106,8 +2128,6 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
num_written = btrfs_buffered_write(iocb, from);
}
- btrfs_inode_unlock(inode, ilock_flags);
-
/*
* We also have to set last_sub_trans to the current log transid,
* otherwise subsequent syncs to a file that's been synced in this
@@ -2123,7 +2143,7 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb,
atomic_dec(&BTRFS_I(inode)->sync_writers);
current->backing_dev_info = NULL;
- return num_written ? num_written : err;
+ return num_written;
}
int btrfs_release_file(struct inode *inode, struct file *filp)
--
2.26.2
