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    Annotation of /trunk/kernel26-magellan/patches-2.6.29-r7/0305-2.6.29-ext4-add-EXT4_IOC_ALLOC_DA_BLKS-ioctl.patch

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    Revision 857 - (hide annotations) (download)
    Tue Jun 30 20:01:52 2009 UTC (14 years, 11 months ago) by niro
    File size: 4130 byte(s) 
    -2.6.29-magellan-r7: updated to linux-2.6.29.5
    1 niro 857 Added-By: Gordon Malm <gengor@gentoo.org>
    2    
    3     ---
    4     From: Theodore Ts'o <tytso@mit.edu>
    5     Date: Thu, 26 Feb 2009 06:04:07 +0000 (-0500)
    6     Subject: ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl
    7     X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftytso%2Fext4.git;a=commitdiff_plain;h=3bf3342f394d72ed2ec7e77b5b39e1b50fad8284
    8    
    9     ext4: add EXT4_IOC_ALLOC_DA_BLKS ioctl
    10    
    11     Add an ioctl which forces all of the delay allocated blocks to be
    12     allocated. This also provides a function ext4_alloc_da_blocks() which
    13     will be used by the following commits to force files to be fully
    14     allocated to preserve application-expected ext3 behaviour.
    15    
    16     Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
    17     ---
    18    
    19     diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
    20     index 684a063..ea51c89 100644
    21     --- a/fs/ext4/ext4.h
    22     +++ b/fs/ext4/ext4.h
    23     @@ -316,7 +316,9 @@ struct ext4_new_group_data {
    24     #define EXT4_IOC_GROUP_EXTEND _IOW('f', 7, unsigned long)
    25     #define EXT4_IOC_GROUP_ADD _IOW('f', 8, struct ext4_new_group_input)
    26     #define EXT4_IOC_MIGRATE _IO('f', 9)
    27     + /* note ioctl 10 reserved for an early version of the FIEMAP ioctl */
    28     /* note ioctl 11 reserved for filesystem-independent FIEMAP ioctl */
    29     +#define EXT4_IOC_ALLOC_DA_BLKS _IO('f', 12)
    30    
    31     /*
    32     * ioctl commands in 32 bit emulation
    33     @@ -1093,6 +1095,7 @@ extern int ext4_can_truncate(struct inode *inode);
    34     extern void ext4_truncate(struct inode *);
    35     extern void ext4_set_inode_flags(struct inode *);
    36     extern void ext4_get_inode_flags(struct ext4_inode_info *);
    37     +extern int ext4_alloc_da_blocks(struct inode *inode);
    38     extern void ext4_set_aops(struct inode *inode);
    39     extern int ext4_writepage_trans_blocks(struct inode *);
    40     extern int ext4_meta_trans_blocks(struct inode *, int nrblocks, int idxblocks);
    41     diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
    42     index c67f46e..ead57ab 100644
    43     --- a/fs/ext4/inode.c
    44     +++ b/fs/ext4/inode.c
    45     @@ -2807,6 +2807,48 @@ out:
    46     return;
    47     }
    48    
    49     +/*
    50     + * Force all delayed allocation blocks to be allocated for a given inode.
    51     + */
    52     +int ext4_alloc_da_blocks(struct inode *inode)
    53     +{
    54     + if (!EXT4_I(inode)->i_reserved_data_blocks &&
    55     + !EXT4_I(inode)->i_reserved_meta_blocks)
    56     + return 0;
    57     +
    58     + /*
    59     + * We do something simple for now. The filemap_flush() will
    60     + * also start triggering a write of the data blocks, which is
    61     + * not strictly speaking necessary (and for users of
    62     + * laptop_mode, not even desirable). However, to do otherwise
    63     + * would require replicating code paths in:
    64     + *
    65     + * ext4_da_writepages() ->
    66     + * write_cache_pages() ---> (via passed in callback function)
    67     + * __mpage_da_writepage() -->
    68     + * mpage_add_bh_to_extent()
    69     + * mpage_da_map_blocks()
    70     + *
    71     + * The problem is that write_cache_pages(), located in
    72     + * mm/page-writeback.c, marks pages clean in preparation for
    73     + * doing I/O, which is not desirable if we're not planning on
    74     + * doing I/O at all.
    75     + *
    76     + * We could call write_cache_pages(), and then redirty all of
    77     + * the pages by calling redirty_page_for_writeback() but that
    78     + * would be ugly in the extreme. So instead we would need to
    79     + * replicate parts of the code in the above functions,
    80     + * simplifying them becuase we wouldn't actually intend to
    81     + * write out the pages, but rather only collect contiguous
    82     + * logical block extents, call the multi-block allocator, and
    83     + * then update the buffer heads with the block allocations.
    84     + *
    85     + * For now, though, we'll cheat by calling filemap_flush(),
    86     + * which will map the blocks, and start the I/O, but not
    87     + * actually wait for the I/O to complete.
    88     + */
    89     + return filemap_flush(inode->i_mapping);
    90     +}
    91    
    92     /*
    93     * bmap() is special. It gets used by applications such as lilo and by
    94     diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
    95     index 22dd29f..91e75f7 100644
    96     --- a/fs/ext4/ioctl.c
    97     +++ b/fs/ext4/ioctl.c
    98     @@ -262,6 +262,20 @@ setversion_out:
    99     return err;
    100     }
    101    
    102     + case EXT4_IOC_ALLOC_DA_BLKS:
    103     + {
    104     + int err;
    105     + if (!is_owner_or_cap(inode))
    106     + return -EACCES;
    107     +
    108     + err = mnt_want_write(filp->f_path.mnt);
    109     + if (err)
    110     + return err;
    111     + err = ext4_alloc_da_blocks(inode);
    112     + mnt_drop_write(filp->f_path.mnt);
    113     + return err;
    114     + }
    115     +
    116     default:
    117     return -ENOTTY;
    118     }