| Message ID | 20141213162403.GF17783@thunk.org |
|---|---|
| State | Accepted, archived |
| Headers | show |
On Dec 13, 2014, at 09:24, Theodore Ts'o <tytso@mit.edu> wrote: > > This is my replacement patch. > > - Ted > > commit 0a92af260da381e2581074871707e487728373ad > Author: Darrick J. Wong <darrick.wong@oracle.com> > Date: Fri Dec 12 18:27:12 2014 -0500 > > libext2fs: use a dynamically sized block zeroing buffer > > Dynamically grow the block zeroing buffer to a maximum of 4MB, and > allow callers to provide their own zeroed buffer in > ext2fs_zero_blocks2(). > > Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> > Signed-off-by: Theodore Ts'o <tytso@mit.edu> > > diff --git a/lib/ext2fs/mkjournal.c b/lib/ext2fs/mkjournal.c > index e8f8b30..fcc6741 100644 > --- a/lib/ext2fs/mkjournal.c > +++ b/lib/ext2fs/mkjournal.c > @@ -148,12 +148,13 @@ errfree: > * attempt to free the static zeroizing buffer. (This is to keep > * programs that check for memory leaks happy.) > */ > -#define STRIDE_LENGTH (4194304 / fs->blocksize) > +#define MAX_STRIDE_LENGTH (4194304 / (int) fs->blocksize) > errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, > blk64_t *ret_blk, int *ret_count) > { > int j, count; > - static char *buf; > + static void *buf; > + static int stride_length; > errcode_t retval; > > /* If fs is null, clean up the static buffer and return */ > @@ -164,24 +165,36 @@ errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, > } > return 0; > } > + > + /* Deal with zeroing less than 1 block */ > + if (num <= 0) > + return 0; > + > /* Allocate the zeroizing buffer if necessary */ > - if (!buf) { > - buf = malloc(fs->blocksize * STRIDE_LENGTH); > - if (!buf) > - return ENOMEM; > - memset(buf, 0, fs->blocksize * STRIDE_LENGTH); > + if (num > stride_length && stride_length < MAX_STRIDE_LENGTH) { > + void *p; > + int new_stride = num; > + > + if (new_stride > MAX_STRIDE_LENGTH) > + new_stride = MAX_STRIDE_LENGTH; > + p = realloc(buf, fs->blocksize * new_stride); > + if (!p) > + return EXT2_ET_NO_MEMORY; Shouldn't this continue using the original buf/num if this realloc fails? Cheers, Andreas > + buf = p; > + stride_length = new_stride; > + memset(buf, 0, fs->blocksize * stride_length); > } > /* OK, do the write loop */ > j=0; > while (j < num) { > - if (blk % STRIDE_LENGTH) { > - count = STRIDE_LENGTH - (blk % STRIDE_LENGTH); > + if (blk % stride_length) { > + count = stride_length - (blk % stride_length); > if (count > (num - j)) > count = num - j; > } else { > count = num - j; > - if (count > STRIDE_LENGTH) > - count = STRIDE_LENGTH; > + if (count > stride_length) > + count = stride_length; > } > retval = io_channel_write_blk64(fs->io, blk, count, buf); > if (retval) { > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" 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/lib/ext2fs/mkjournal.c b/lib/ext2fs/mkjournal.c index e8f8b30..fcc6741 100644 --- a/lib/ext2fs/mkjournal.c +++ b/lib/ext2fs/mkjournal.c @@ -148,12 +148,13 @@ errfree: * attempt to free the static zeroizing buffer. (This is to keep * programs that check for memory leaks happy.) */ -#define STRIDE_LENGTH (4194304 / fs->blocksize) +#define MAX_STRIDE_LENGTH (4194304 / (int) fs->blocksize) errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, blk64_t *ret_blk, int *ret_count) { int j, count; - static char *buf; + static void *buf; + static int stride_length; errcode_t retval; /* If fs is null, clean up the static buffer and return */ @@ -164,24 +165,36 @@ errcode_t ext2fs_zero_blocks2(ext2_filsys fs, blk64_t blk, int num, } return 0; } + + /* Deal with zeroing less than 1 block */ + if (num <= 0) + return 0; + /* Allocate the zeroizing buffer if necessary */ - if (!buf) { - buf = malloc(fs->blocksize * STRIDE_LENGTH); - if (!buf) - return ENOMEM; - memset(buf, 0, fs->blocksize * STRIDE_LENGTH); + if (num > stride_length && stride_length < MAX_STRIDE_LENGTH) { + void *p; + int new_stride = num; + + if (new_stride > MAX_STRIDE_LENGTH) + new_stride = MAX_STRIDE_LENGTH; + p = realloc(buf, fs->blocksize * new_stride); + if (!p) + return EXT2_ET_NO_MEMORY; + buf = p; + stride_length = new_stride; + memset(buf, 0, fs->blocksize * stride_length); } /* OK, do the write loop */ j=0; while (j < num) { - if (blk % STRIDE_LENGTH) { - count = STRIDE_LENGTH - (blk % STRIDE_LENGTH); + if (blk % stride_length) { + count = stride_length - (blk % stride_length); if (count > (num - j)) count = num - j; } else { count = num - j; - if (count > STRIDE_LENGTH) - count = STRIDE_LENGTH; + if (count > stride_length) + count = stride_length; } retval = io_channel_write_blk64(fs->io, blk, count, buf); if (retval) {
This is my replacement patch. - Ted commit 0a92af260da381e2581074871707e487728373ad Author: Darrick J. Wong <darrick.wong@oracle.com> Date: Fri Dec 12 18:27:12 2014 -0500 libext2fs: use a dynamically sized block zeroing buffer Dynamically grow the block zeroing buffer to a maximum of 4MB, and allow callers to provide their own zeroed buffer in ext2fs_zero_blocks2(). Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu> -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html