ext4: avoid deadlocks in the writeback path by using sb_getblk_gfp

commit c45653c341f5c8a0ce19c8f0ad4678640849cb86 upstream.

Switch ext4 to using sb_getblk_gfp with GFP_NOFS added to fix possible
deadlocks in the page writeback path.

Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index e003a1e..87ba10d 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -503,7 +503,7 @@ __read_extent_tree_block(const char *function, unsigned int line,
        struct buffer_head              *bh;
        int                             err;
 
-       bh = sb_getblk(inode->i_sb, pblk);
+       bh = sb_getblk_gfp(inode->i_sb, pblk, __GFP_MOVABLE | GFP_NOFS);
        if (unlikely(!bh))
                return ERR_PTR(-ENOMEM);
 
@@ -1088,7 +1088,7 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
                err = -EIO;
                goto cleanup;
        }
-       bh = sb_getblk(inode->i_sb, newblock);
+       bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
        if (unlikely(!bh)) {
                err = -ENOMEM;
                goto cleanup;
@@ -1282,7 +1282,7 @@ static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
        if (newblock == 0)
                return err;
 
-       bh = sb_getblk(inode->i_sb, newblock);
+       bh = sb_getblk_gfp(inode->i_sb, newblock, __GFP_MOVABLE | GFP_NOFS);
        if (unlikely(!bh))
                return -ENOMEM;
        lock_buffer(bh);