4.14-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jeff Mahoney <[email protected]>

[ Upstream commit a8fd1f71749387c9a1053a83ff1c16287499a4e7 ]

The srcu_struct in btrfs_fs_info scales in size with NR_CPUS.  On
kernels built with NR_CPUS=8192, this can result in kmalloc failures
that prevent mounting.

There is work in progress to try to resolve this for every user of
srcu_struct but using kvzalloc will work around the failures until
that is complete.

As an example with NR_CPUS=512 on x86_64: the overall size of
subvol_srcu is 3460 bytes, fs_info is 6496.

Signed-off-by: Jeff Mahoney <[email protected]>
Reviewed-by: David Sterba <[email protected]>
Signed-off-by: David Sterba <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 fs/btrfs/ctree.h |    2 +-
 fs/btrfs/super.c |    2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

--- a/fs/btrfs/ctree.h
+++ b/fs/btrfs/ctree.h
@@ -2969,7 +2969,7 @@ static inline void free_fs_info(struct b
        kfree(fs_info->super_copy);
        kfree(fs_info->super_for_commit);
        security_free_mnt_opts(&fs_info->security_opts);
-       kfree(fs_info);
+       kvfree(fs_info);
 }
 
 /* tree mod log functions from ctree.c */
--- a/fs/btrfs/super.c
+++ b/fs/btrfs/super.c
@@ -1581,7 +1581,7 @@ static struct dentry *btrfs_mount(struct
         * it for searching for existing supers, so this lets us do that and
         * then open_ctree will properly initialize everything later.
         */
-       fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
+       fs_info = kvzalloc(sizeof(struct btrfs_fs_info), GFP_KERNEL);
        if (!fs_info) {
                error = -ENOMEM;
                goto error_sec_opts;


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