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authorGoldwyn Rodrigues <rgoldwyn@suse.com>2017-06-20 07:05:47 -0500
committerJens Axboe <axboe@kernel.dk>2017-06-20 07:12:03 -0600
commit728fbc0e10b7f3ce2ee043b32e3453fd5201c055 (patch)
treeeff612a5bd8832bb002d3adde66a9b6c5a475f6d /fs/ext4/file.c
parent03a07c92a9ed9938d828ca7f1d11b8bc63a7bb89 (diff)
ext4: nowait aio support
Return EAGAIN if any of the following checks fail for direct I/O: + i_rwsem is lockable + Writing beyond end of file (will trigger allocation) + Blocks are not allocated at the write location Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'fs/ext4/file.c')
-rw-r--r--fs/ext4/file.c35
1 files changed, 29 insertions, 6 deletions
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 02ce7e7bbdf5..58e2eeaa0bc4 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c
@@ -37,7 +37,11 @@ static ssize_t ext4_dax_read_iter(struct kiocb *iocb, struct iov_iter *to)
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
- inode_lock_shared(inode);
+ if (!inode_trylock_shared(inode)) {
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EAGAIN;
+ inode_lock_shared(inode);
+ }
/*
* Recheck under inode lock - at this point we are sure it cannot
* change anymore
@@ -179,7 +183,11 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from)
struct inode *inode = file_inode(iocb->ki_filp);
ssize_t ret;
- inode_lock(inode);
+ if (!inode_trylock(inode)) {
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EAGAIN;
+ inode_lock(inode);
+ }
ret = ext4_write_checks(iocb, from);
if (ret <= 0)
goto out;
@@ -216,7 +224,12 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
return ext4_dax_write_iter(iocb, from);
#endif
- inode_lock(inode);
+ if (!inode_trylock(inode)) {
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return -EAGAIN;
+ inode_lock(inode);
+ }
+
ret = ext4_write_checks(iocb, from);
if (ret <= 0)
goto out;
@@ -235,9 +248,15 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
iocb->private = &overwrite;
/* Check whether we do a DIO overwrite or not */
- if (o_direct && ext4_should_dioread_nolock(inode) && !unaligned_aio &&
- ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from)))
- overwrite = 1;
+ if (o_direct && !unaligned_aio) {
+ if (ext4_overwrite_io(inode, iocb->ki_pos, iov_iter_count(from))) {
+ if (ext4_should_dioread_nolock(inode))
+ overwrite = 1;
+ } else if (iocb->ki_flags & IOCB_NOWAIT) {
+ ret = -EAGAIN;
+ goto out;
+ }
+ }
ret = __generic_file_write_iter(iocb, from);
inode_unlock(inode);
@@ -435,6 +454,10 @@ static int ext4_file_open(struct inode * inode, struct file * filp)
if (ret < 0)
return ret;
}
+
+ /* Set the flags to support nowait AIO */
+ filp->f_mode |= FMODE_AIO_NOWAIT;
+
return dquot_file_open(inode, filp);
}