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authorOmar Sandoval <osandov@fb.com>2021-08-12 15:34:57 -0700
committerDavid Sterba <dsterba@suse.com>2022-03-14 13:13:50 +0100
commitf6f7a25a650818c61defa97d60a79b216618315f (patch)
tree9e347008104e54d5ab694e8dc0e941d54ff852fc
parent871129332d74c9e94bd110932ac4445833995639 (diff)
downloadlinux-f6f7a25a650818c61defa97d60a79b216618315f.tar.bz2
fs: export variant of generic_write_checks without iov_iter
Encoded I/O in Btrfs needs to check a write with a given logical size without an iov_iter that matches that size (because the iov_iter we have is for the compressed data). So, factor out the parts of generic_write_check() that don't need an iov_iter into a new generic_write_checks_count() function and export that. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
-rw-r--r--fs/read_write.c33
-rw-r--r--include/linux/fs.h1
2 files changed, 21 insertions, 13 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 4d60146243df..dc5000173b80 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1618,24 +1618,16 @@ int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count)
return 0;
}
-/*
- * Performs necessary checks before doing a write
- *
- * Can adjust writing position or amount of bytes to write.
- * Returns appropriate error code that caller should return or
- * zero in case that write should be allowed.
- */
-ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
+/* Like generic_write_checks(), but takes size of write instead of iter. */
+int generic_write_checks_count(struct kiocb *iocb, loff_t *count)
{
struct file *file = iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
- loff_t count;
- int ret;
if (IS_SWAPFILE(inode))
return -ETXTBSY;
- if (!iov_iter_count(from))
+ if (!*count)
return 0;
/* FIXME: this is for backwards compatibility with 2.4 */
@@ -1645,8 +1637,23 @@ ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
return -EINVAL;
- count = iov_iter_count(from);
- ret = generic_write_check_limits(file, iocb->ki_pos, &count);
+ return generic_write_check_limits(iocb->ki_filp, iocb->ki_pos, count);
+}
+EXPORT_SYMBOL(generic_write_checks_count);
+
+/*
+ * Performs necessary checks before doing a write
+ *
+ * Can adjust writing position or amount of bytes to write.
+ * Returns appropriate error code that caller should return or
+ * zero in case that write should be allowed.
+ */
+ssize_t generic_write_checks(struct kiocb *iocb, struct iov_iter *from)
+{
+ loff_t count = iov_iter_count(from);
+ int ret;
+
+ ret = generic_write_checks_count(iocb, &count);
if (ret)
return ret;
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 0ebfc2519212..27746a3da8fd 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -3130,6 +3130,7 @@ extern int sb_min_blocksize(struct super_block *, int);
extern int generic_file_mmap(struct file *, struct vm_area_struct *);
extern int generic_file_readonly_mmap(struct file *, struct vm_area_struct *);
extern ssize_t generic_write_checks(struct kiocb *, struct iov_iter *);
+int generic_write_checks_count(struct kiocb *iocb, loff_t *count);
extern int generic_write_check_limits(struct file *file, loff_t pos,
loff_t *count);
extern int generic_file_rw_checks(struct file *file_in, struct file *file_out);