| Message ID | 6174e7ce0e55e54a1a4c3a6be413885495926728.1496252765.git.dsterba@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 06/01/17 01:49, David Sterba wrote: > 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> Thanks, Anand > Signed-off-by: David Sterba <dsterba@suse.com> > --- > fs/btrfs/scrub.c | 9 +++++++++ > 1 file changed, 9 insertions(+) > > 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; > -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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;
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 Signed-off-by: David Sterba <dsterba@suse.com> --- fs/btrfs/scrub.c | 9 +++++++++ 1 file changed, 9 insertions(+)