[PATCH v2] xfs: Check for deallayed allocations before setting extsize

[Ojaswin Mujoo <ojaswin@linux.ibm.com>]

Extsize is allowed to be set on files with no data in it. For this,
we were checking if the files have extents but missed to check if
delayed extents were present. This patch adds that check.

While we are at it, also refactor this check into a helper since
its used in some other places as well like xfs_inactive() or
xfs_ioctl_setattr_xflags()

**Without the patch (SUCCEEDS)**

$ xfs_io -c 'open -f testfile' -c 'pwrite 0 1024' -c 'extsize 65536'

wrote 1024/1024 bytes at offset 0
1 KiB, 1 ops; 0.0002 sec (4.628 MiB/sec and 4739.3365 ops/sec)

**With the patch (FAILS as expected)**

$ xfs_io -c 'open -f testfile' -c 'pwrite 0 1024' -c 'extsize 65536'

wrote 1024/1024 bytes at offset 0
1 KiB, 1 ops; 0.0002 sec (4.628 MiB/sec and 4739.3365 ops/sec)
xfs_io: FS_IOC_FSSETXATTR testfile: Invalid argument

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
---

* Changes since v1 *

 - RVB by Christoph
 - Added a helper to check if inode has data instead of
   open coding.
	
v1:
https://lore.kernel.org/linux-xfs/Zv_cTc6cgxszKGy3@infradead.org/T/#mf949dafb2b2f63bea1f7c0ce5265a2527aaf22a9

 fs/xfs/xfs_inode.c | 2 +-
 fs/xfs/xfs_inode.h | 5 +++++
 fs/xfs/xfs_ioctl.c | 5 +++--
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/fs/xfs/xfs_inode.c b/fs/xfs/xfs_inode.c
index bcc277fc0a83..3d083a8fd8ed 100644
--- a/fs/xfs/xfs_inode.c
+++ b/fs/xfs/xfs_inode.c
@@ -1409,7 +1409,7 @@ xfs_inactive(
 
 	if (S_ISREG(VFS_I(ip)->i_mode) &&
 	    (ip->i_disk_size != 0 || XFS_ISIZE(ip) != 0 ||
-	     ip->i_df.if_nextents > 0 || ip->i_delayed_blks > 0))
+	     xfs_inode_has_data(ip)))
 		truncate = 1;
 
 	if (xfs_iflags_test(ip, XFS_IQUOTAUNCHECKED)) {
diff --git a/fs/xfs/xfs_inode.h b/fs/xfs/xfs_inode.h
index 97ed912306fd..ae1ccf2a3c8b 100644
--- a/fs/xfs/xfs_inode.h
+++ b/fs/xfs/xfs_inode.h
@@ -292,6 +292,11 @@ static inline bool xfs_is_cow_inode(struct xfs_inode *ip)
 	return xfs_is_reflink_inode(ip) || xfs_is_always_cow_inode(ip);
 }
 
+static inline bool xfs_inode_has_data(struct xfs_inode *ip)
+{
+	return (ip->i_df.if_nextents > 0 || ip->i_delayed_blks > 0);
+}
+
 /*
  * Check if an inode has any data in the COW fork.  This might be often false
  * even for inodes with the reflink flag when there is no pending COW operation.
diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index a20d426ef021..88b9c8cf0272 100644
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -481,7 +481,7 @@ xfs_ioctl_setattr_xflags(
 
 	if (rtflag != XFS_IS_REALTIME_INODE(ip)) {
 		/* Can't change realtime flag if any extents are allocated. */
-		if (ip->i_df.if_nextents || ip->i_delayed_blks)
+		if (xfs_inode_has_data(ip))
 			return -EINVAL;
 
 		/*
@@ -602,7 +602,8 @@ xfs_ioctl_setattr_check_extsize(
 	if (!fa->fsx_valid)
 		return 0;
 
-	if (S_ISREG(VFS_I(ip)->i_mode) && ip->i_df.if_nextents &&
+	if (S_ISREG(VFS_I(ip)->i_mode) &&
+	    xfs_inode_has_data(ip) &&
 	    XFS_FSB_TO_B(mp, ip->i_extsize) != fa->fsx_extsize)
 		return -EINVAL;
 
-- 
2.43.5