ext4: prevent ext4_quota_write() from failing due to ENOSPC

In order to prevent quota block tracking to be inaccurate when
ext4_quota_write() fails with ENOSPC, we make two changes.  The quota
file can now use the reserved block (since the quota file is arguably
file system metadata), and ext4_quota_write() now uses
ext4_should_retry_alloc() to retry the block allocation after a commit
has completed and released some blocks for allocation.

This fixes failures of xfstests generic/270:

Quota error (device vdc): write_blk: dquota write failed
Quota error (device vdc): qtree_write_dquot: Error -28 occurred while creating quota

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 1ba8b4ab03a8955baffb2a1bbd97e103d063d629..d86d2622f82631f3fa46abe1047caf319b968402 100644 (file)
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4456,6 +4456,8 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
                ar.flags |= EXT4_MB_HINT_NOPREALLOC;
        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
                ar.flags |= EXT4_MB_DELALLOC_RESERVED;
+       if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
+               ar.flags |= EXT4_MB_USE_RESERVED;
        newblock = ext4_mb_new_blocks(handle, &ar, &err);
        if (!newblock)
                goto out2;

diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 9588240195090ce4216e87f07379121b4ffe6cfb..9962d577bad5d7c7fc8f3162804298e96fbf34ab 100644 (file)
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -576,6 +576,8 @@ int ext4_ind_map_blocks(handle_t *handle, struct inode *inode,
                ar.flags = EXT4_MB_HINT_DATA;
        if (flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE)
                ar.flags |= EXT4_MB_DELALLOC_RESERVED;
+       if (flags & EXT4_GET_BLOCKS_METADATA_NOFAIL)
+               ar.flags |= EXT4_MB_USE_RESERVED;
 
        ar.goal = ext4_find_goal(inode, map->m_lblk, partial);
 

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 263a46c488c73fe795fd5083bfd826215ca3afc4..e8a67b8ba90c39712712c47a124fa5a721e29a46 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -731,18 +731,18 @@ int ext4_get_block(struct inode *inode, sector_t iblock,
  * `handle' can be NULL if create is zero
  */
 struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
-                               ext4_lblk_t block, int create)
+                               ext4_lblk_t block, int map_flags)
 {
        struct ext4_map_blocks map;
        struct buffer_head *bh;
+       int create = map_flags & EXT4_GET_BLOCKS_CREATE;
        int err;
 
        J_ASSERT(handle != NULL || create == 0);
 
        map.m_lblk = block;
        map.m_len = 1;
-       err = ext4_map_blocks(handle, inode, &map,
-                             create ? EXT4_GET_BLOCKS_CREATE : 0);
+       err = ext4_map_blocks(handle, inode, &map, map_flags);
 
        if (err == 0)
                return create ? ERR_PTR(-ENOSPC) : NULL;
@@ -788,11 +788,11 @@ errout:
 }
 
 struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
-                              ext4_lblk_t block, int create)
+                              ext4_lblk_t block, int map_flags)
 {
        struct buffer_head *bh;
 
-       bh = ext4_getblk(handle, inode, block, create);
+       bh = ext4_getblk(handle, inode, block, map_flags);
        if (IS_ERR(bh))
                return bh;
        if (!bh || buffer_uptodate(bh))

diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 5e7676f1e82f910f2b1e1d2934973fd75ef02a3b..e230b31251f7f18de48e70f64f794d36c71ecb5e 100644 (file)
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -61,7 +61,7 @@ static struct buffer_head *ext4_append(handle_t *handle,
 
        *block = inode->i_size >> inode->i_sb->s_blocksize_bits;
 
-       bh = ext4_bread(handle, inode, *block, 1);
+       bh = ext4_bread(handle, inode, *block, EXT4_GET_BLOCKS_CREATE);
        if (IS_ERR(bh))
                return bh;
        inode->i_size += inode->i_sb->s_blocksize;

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 2858ac09f5a391bcdccbf430fa67da18c617ec68..bd4df9d379b2f162b20f65cc24c18bc3442069fb 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5438,6 +5438,7 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type,
        struct inode *inode = sb_dqopt(sb)->files[type];
        ext4_lblk_t blk = off >> EXT4_BLOCK_SIZE_BITS(sb);
        int err, offset = off & (sb->s_blocksize - 1);
+       int retries = 0;
        struct buffer_head *bh;
        handle_t *handle = journal_current_handle();
 
@@ -5458,7 +5459,12 @@ static ssize_t ext4_quota_write(struct super_block *sb, int type,
                return -EIO;
        }
 
-       bh = ext4_bread(handle, inode, blk, 1);
+       do {
+               bh = ext4_bread(handle, inode, blk,
+                               EXT4_GET_BLOCKS_CREATE |
+                               EXT4_GET_BLOCKS_METADATA_NOFAIL);
+       } while (IS_ERR(bh) && (PTR_ERR(bh) == -ENOSPC) &&
+                ext4_should_retry_alloc(inode->i_sb, &retries));
        if (IS_ERR(bh))
                return PTR_ERR(bh);
        if (!bh)