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| author | David Sterba <dsterba@suse.com> | 2017-05-31 20:21:38 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2017-06-19 19:26:02 +0300 |
| commit | de2491fdefe7e599fa08a81a1b89d03c96c9cbc3 (patch) | |
| tree | b3fd451798e685ab306e10bbc842303d7aecace0 | |
| parent | f11f74416ae6e63a6d6db9c5b22666a0aa57b881 (diff) | |
| download | linux-de2491fdefe7e599fa08a81a1b89d03c96c9cbc3.tar.xz | |
btrfs: scrub: add memalloc_nofs protection around init_ipath
init_ipath is called from a safe ioctl context and from scrub when
printing an error. The protection is added for three reasons:
* init_data_container calls vmalloc and this does not work as expected
in the GFP_NOFS context, so this silently does GFP_KERNEL and might
deadlock in some cases
* keep the context constraint of GFP_NOFS, used by scrub
* we want to use GFP_KERNEL unconditionally inside init_ipath or its
callees
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/scrub.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index e99be644b19f..096e503e3ddc 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -18,6 +18,7 @@ #include <linux/blkdev.h> #include <linux/ratelimit.h> +#include <linux/sched/mm.h> #include "ctree.h" #include "volumes.h" #include "disk-io.h" @@ -733,6 +734,7 @@ static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, u32 nlink; int ret; int i; + unsigned nofs_flag; struct extent_buffer *eb; struct btrfs_inode_item *inode_item; struct scrub_warning *swarn = warn_ctx; @@ -771,7 +773,14 @@ static int scrub_print_warning_inode(u64 inum, u64 offset, u64 root, nlink = btrfs_inode_nlink(eb, inode_item); btrfs_release_path(swarn->path); + /* + * init_path might indirectly call vmalloc, or use GFP_KERNEL. Scrub + * uses GFP_NOFS in this context, so we keep it consistent but it does + * not seem to be strictly necessary. + */ + nofs_flag = memalloc_nofs_save(); ipath = init_ipath(4096, local_root, swarn->path); + memalloc_nofs_restore(nofs_flag); if (IS_ERR(ipath)) { ret = PTR_ERR(ipath); ipath = NULL; |