NTFS: Use ntfs_malloc_nofs_nofail() in runlist.c::ntfs_runlists_merge()
in the two critical regions. This means we no longer need to panic() when the allocation fails as it now cannot fail. Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
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@ -40,6 +40,9 @@ ToDo/Notes:
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- Add fs/ntfs/malloc.h::ntfs_malloc_nofs_nofail() which is analogous to
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ntfs_malloc_nofs() but it performs allocations with __GFP_NOFAIL and
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hence cannot fail.
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- Use ntfs_malloc_nofs_nofail() in the two critical regions in
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fs/ntfs/runlist.c::ntfs_runlists_merge(). This means we no longer
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need to panic() if the allocation fails as it now cannot fail.
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2.1.23 - Implement extension of resident files and make writing safe as well as
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many bug fixes, cleanups, and enhancements...
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@ -94,6 +94,51 @@ static inline runlist_element *ntfs_rl_realloc(runlist_element *rl,
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return new_rl;
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}
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/**
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* ntfs_rl_realloc_nofail - Reallocate memory for runlists
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* @rl: original runlist
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* @old_size: number of runlist elements in the original runlist @rl
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* @new_size: number of runlist elements we need space for
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*
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* As the runlists grow, more memory will be required. To prevent the
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* kernel having to allocate and reallocate large numbers of small bits of
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* memory, this function returns an entire page of memory.
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*
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* This function guarantees that the allocation will succeed. It will sleep
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* for as long as it takes to complete the allocation.
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*
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* It is up to the caller to serialize access to the runlist @rl.
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*
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* N.B. If the new allocation doesn't require a different number of pages in
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* memory, the function will return the original pointer.
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*
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* On success, return a pointer to the newly allocated, or recycled, memory.
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* On error, return -errno. The following error codes are defined:
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* -ENOMEM - Not enough memory to allocate runlist array.
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* -EINVAL - Invalid parameters were passed in.
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*/
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static inline runlist_element *ntfs_rl_realloc_nofail(runlist_element *rl,
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int old_size, int new_size)
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{
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runlist_element *new_rl;
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old_size = PAGE_ALIGN(old_size * sizeof(*rl));
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new_size = PAGE_ALIGN(new_size * sizeof(*rl));
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if (old_size == new_size)
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return rl;
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new_rl = ntfs_malloc_nofs_nofail(new_size);
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BUG_ON(!new_rl);
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if (likely(rl != NULL)) {
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if (unlikely(old_size > new_size))
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old_size = new_size;
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memcpy(new_rl, rl, old_size);
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ntfs_free(rl);
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}
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return new_rl;
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}
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/**
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* ntfs_are_rl_mergeable - test if two runlists can be joined together
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* @dst: original runlist
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@ -621,11 +666,8 @@ runlist_element *ntfs_runlists_merge(runlist_element *drl,
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if (drl[ds].lcn != LCN_RL_NOT_MAPPED) {
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/* Add an unmapped runlist element. */
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if (!slots) {
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/* FIXME/TODO: We need to have the
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* extra memory already! (AIA) */
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drl = ntfs_rl_realloc(drl, ds, ds + 2);
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if (!drl)
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goto critical_error;
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drl = ntfs_rl_realloc_nofail(drl, ds,
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ds + 2);
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slots = 2;
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}
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ds++;
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@ -640,13 +682,8 @@ runlist_element *ntfs_runlists_merge(runlist_element *drl,
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drl[ds].length = marker_vcn - drl[ds].vcn;
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/* Finally add the ENOENT terminator. */
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ds++;
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if (!slots) {
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/* FIXME/TODO: We need to have the extra
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* memory already! (AIA) */
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drl = ntfs_rl_realloc(drl, ds, ds + 1);
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if (!drl)
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goto critical_error;
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}
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if (!slots)
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drl = ntfs_rl_realloc_nofail(drl, ds, ds + 1);
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drl[ds].vcn = marker_vcn;
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drl[ds].lcn = LCN_ENOENT;
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drl[ds].length = (s64)0;
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@ -659,11 +696,6 @@ finished:
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ntfs_debug("Merged runlist:");
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ntfs_debug_dump_runlist(drl);
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return drl;
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critical_error:
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/* Critical error! We cannot afford to fail here. */
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ntfs_error(NULL, "Critical error! Not enough memory.");
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panic("NTFS: Cannot continue.");
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}
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/**
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